Remote Detonator
This ability allows you to plant a packed explosive mine which you can then detonate at your own choosing. The base ability is an explosive Area of Effect attack which does 3000 damage. The boxes further down the line don't add very much to the ability. You simply get a debuff, shorter cooldown, and a bigger blast radius, but the last box in the line is a critical one. "Improved Explosives" boosts the damage of this attack by 60% for a total damage of 4880. This makes it the single most damaging AoE attack in the game before DoTs. However, it has a rather lengthy cooldown at 2 minutes. This limits the use of remote detonator to basically once per encounter.
NOTE: Unless you invest in the entire line and get all four points in the last box, your points are wasted. If you pick up all of "Improved Explosives" then your points are assuredly not wasted. It's a take-all or none-at-all skill-set.
Suppressing Fire
Suppressing fire is a multiple target cone of fire ranged weapon debuff which incurs a glancing blow penalty on all of your affected targets' attacks. The base ability will cause 10% of your opponents attacks to glance, but if you pick up the box above it you'll get an additional 5% per point spent. With the entire enhancement box that's 30% of your target's attacks glancing. It is also heavy weapon-compatible, meaning you can lay it down on a target with that rocket or acid launcher. This debuff lasts 8 seconds and has a 30 second cooldown.
NOTE: This is quite possibly one of the best abilities in our expertise. I would recommend you pick it up and its enhancement box. Valuable in both PvE and PvP plus its cone of effect is fairly wide.
Riddle Armor
Another great ability, riddle armor is a single target focus fire ranged weapon debuff which lowers the resistances of your target's armor. The base ability will lower the target's armor resistance by 1000 points across the board. The enhancement line adds an additional -500 points to the ability per point spent for a total -3000 armor break. For a comparison, capped battle armor (6000 resistances) mitigates 48.5% of all incoming damage. After armor break that mitigation is lowered to 28.5%, so that's a 20% damage increase. As is the case with suppressing fire, this debuff is heavy weapon compatible. This debuff lasts 15 seconds and has a 30 second cooldown.
NOTE: Riddle Armor and its entire enhancement box is a must have for any commando. It allows you to pour a lot more damage into targets which is extremely valuable against both players and elite mobs, which are often heavily armored.
Powered Armor & Pinpoint Shielding
Both of these boxes add 250 points to your armor resistances per point spent. This armor is innate and will always be on your character even if no armor is equipped. The total armor resistance upgrade is a 2000 point bonus to all resistances.
NOTE: Take both boxes for the entire 2000 point bonus. These are mandatory for any effective Commando.
Deflective Armor
Deflective Armor reduces all incoming damage by 1% per point spent, but the way it's calculated reduces that "on paper" mitigation considerably. Deflective armor is calculated after damage is mitigated by armor, so it's not reducing the attack damage by 1% per point spent, it's reducing the after armor damage by 1% per point spent. In realistic terms, even if you took this entire box it's only going to actually reduce approximately 1.76% of the damage of each attack.
NOTE: Not worth taking, especially considering the costs associated and the minimal gain in defense.
Stim Armor
This is a heal over time that lasts 32 seconds. It heals you 500 health every 6 seconds for a total heal of 3000.
NOTE: It's our only heal enhancement in our expertise and it only costs a single point. You should definitely take this enhancement.
Diagnostic Armor
Diagnostic armor innately reduces DoT damage by 25% per point spent.
NOTE: A worthless skill unless you PvP as very few NPC mobs inflict DoTs. In PvP it can be valuable, particularly against other commandos.
Mirrored Armor
Mirrored Armor will make you appear invisible on other players' radars. It lasts 2 minutes and has a 4 minute cooldown.
NOTE: Has no effect in PvE, but can come in very handy if you PvP.
Kill Meter System of Expertise
The following abilities are all part of the kill meter system of expertise. The kill meter is a simple gauge that ranges from 0-50 which tracks the amount of objects (both player and NPC) you have killed in a given amount of time. As the kill meter increases towards its maximum value of 50 the abilities below will either increase in potency or have their chance of execution increase. The kills on the kill meter decay over time. The more kills you have, the faster the rate of decay.
It Burns - Each kill on the kill meter will increase the chance to land a -75 fire DoT on your target by 1%. Each point spent will add 2 seconds of duration to the fire DoT. This is not compatible with heavy weapons and it will not stack with a heavy weapon fire DoT.
Blow'em Away - Each kill on the kill meter will increase grenade damage by 1%.
Killing Grimace - Each kill on the commandos kill meter will increase weapon damage by 1%.
Armor Splash - Each kill on the kill meter will increase the chance to land a -100 acid DoT on your target by 1%. Each point spent will add 2 seconds of duration to the acid DoT. This is not compatible with heavy weapons and it will not stack with a heavy weapon fire DoT.
You'll Regret That - Each kill on the commando's kill meter increases the chance to get a 1000 armor bonus per point spent when stunned (snared, rooted, etc).
NOTE: The two DoT boxes aren't compatible with Heavy Weapons and aren't particularly potent either. Most Commandos rely on heavy weapons which disable all grenade attacks, so that limits the usefulness of "Blow'em Away." "Killing Grimace" and "You'll Regret That" are the two best kill meter abilities to pick up overall.
Assault
Position Secured - Will root a player in place in exchange for a +200 precision bonus The following boxes will enhance the base ability.
Burst Fire - This enhancement will give you a 20% chance per point spent to innately return an attacker's attack and also increase your chance to land a devastating strike by 5% per point spent. The chance to return fire is incompatible with heavy weapons.
On Target - This enhancement increases your chance to land a critical hit by 3% per point spent as well as give you a 5% chance to block a critical attack per point spent.
Base of Operations - This ability is a group buff which gives your group a 500 armor resistance bonus which lasts ten minutes.
NOTE: I don't recommend any aspects of this expertise line for PvP, simply considering the fact that you are rooted for a considerable amount of time and it has little overall effect to your enhancements and abilities. However, many people believe in the usefulness of this ability in PvE instances.
Ranged Weapons Enhancement
This line of expertise will enhance ranged weapons (including heavy weapons) and your non-heavy weapon focus fire special attacks.
Hose Down - This enhancement will decrease the action cost of all focus fire attacks (excessive force, shock tracer, etc) by 5% per point spent (2 points maximum).
Keen Eye - This enhancement will increase weapon range by 4 meters per point spent (2 points maximum) not to exceed 64 meters.
Heavy Ammunition - This enhancement will increase all ranged weapons' damage by 2% per point spent (4 points maximum).
NOTE: This can be a very useful enhancement line as heavy ammunition boosts the damage of heavy weapons as well as regular ranged weapons. In addition, you can increase flamethrower, pistol, and carbine range as well as decrease the action cost of excessive force and shock tracer.
Grenade Enhancements
This line of expertise will enhance all of your grenade specials.
Blast Radius - This enhancement increases the blast radius of grenades by 1 meter per point spent (4 points maximum).
Strong Arm - This enhancement reduces the action cost of grenade attacks by 2% per point spent (4 points maximum).
Packed Explosives - This enhancement increases grenade damage by 2% per point spent (4 points maximum).
Blast Resistance - This enhancement gives you a 5% chance to fully resist AoE damage per point spent (4 points maximum).
NOTE: Grenades are limited in their usefulness as is and the entire enhancement line is prohibitively expensive in terms of the returns (4 points in every single box). "Blast Resistance" could be very useful, but the point cost to get that box will eat up a lot of your points. For this reason I don't recommend any aspects of this line except "Blast Radius."
Electrical Warfare
This line consists of two new abilities and their enhancements. The feature of the shock line is that the attacks will land -400 electrical DoT.
Shock Tracer - A focus fire attack that hits for 3000 damage and sticks a -300 electrical DoT for 3 seconds. It has a 10 second cooldown. As with all focus fire attacks it cannot be used with heavy weapons.
Voltage Overload - Increases the DoT duration by 4 seconds per point spent (2 points maximum).
Muscle Spasm - Adds a debuff to the shock attacks which will cause the affected target to suffer a 2% glancing blow chance per attack per point spent (4 points maximum).
Shock Grenade - A sum of everything previous to this box except wrapped up inside of an AoE grenade attack.
NOTE: A great line of abilities, especially for the commandos who aren't so reliant on heavy weapons.
Weighing Your Options
The tease of Commando has always been heavy weapons and our expertise offers numerous methods of enhancing them. However, it can also accommodate Commandos who choose to rely on regular weapons and movement so we aren't shoe-horned into a specific play style.
When you contemplate which abilities you want to pick up you need to make a conscious decision of what type of commando you want to be. Do you want be a "terminator" unleashing major heavy weapon pain on all of your enemies or do you prefer a more "special forces" approach based on regular weapons, grenades and special attacks?
Essential Expertise
The following expertise boxes are ones which any and all commandos will agree are absolutely essential regardless of your playing style:
-Suppressing Fire (and all of Suppression Efficiency);
-Powered Armor;
-Pinpoint Shielding;
-Stim Armor; and
-Constitution Bonus.
Shock Trooper Options
The following expertise boxes are recommended for those commandos who wish to focus on heavy weapon proficiency:
-Killing Grimace; and
-Heavy Ammunition.
Special Forces Options
The following expertise boxes are highly recommended for those commandos who do not wish to rely on heavy weapons:
-Shock Tracer;
-Voltage Overload;
-Keen Eye; and
-Remote Detonator.
PvP Options
The following expertise boxes are highly recommended for PvP:
-Mirrored Armor;
-Riddle Armor (and all of Armor Cracker); and
-Diagnostic Armor.
That's all you need to know on Commando Expertise. Good luck out there, and give 'em hell!