Re: [A full review of Admec](and what we can do with them.)
I was reading this thread from last year and I generally agree with a lot of the author's general arguments, but I do want to touch on some things that I don't think really got touched on. I don't have much multiplayer experience, largely because it takes so long to find a match, but I wanted to combine a few things Myridus had brought up with some things I've been playing around-with in Skirmish.
First off: The Adeptus Mechanicus get some of the best control abilities in the game, suitable for both Skirmish battles and the Campaign. Not only do they get access to Stasis Bomb, pretty much the go-to movement control device, but they also get the Eye of the Omnissiah, which I find is a fantastic ability. Mechadominator is, while less useful in PvP or skirmish fights, incredibly useful for certain objectives in the campaign, so much so that it feels tailor-made for the Data Recovery sub-mission or those missions where you aren't allowed to let X ship disengage.
Now, control is one thing, but I'm sure many people realize that the range for Stasis Bomb or Mechadominator is much smaller than the range of a Nova Canon and means you have to put your flagship in some amount of risk for what may simply not be good-enough gains. Novas do a lot of damage, but full shields or Supercharged Void Shields can really put a dent in your plans with them. However, the Adeptus Mechanicus get access to another ability that also works extremely well with their powerful control options: the Rad-Tempest Device.
The Rad-Tempest Device creates a pretty blue swirling storm of death in a sizeable area and lasts for 45 seconds. It deals 20 damage per second that ignores both armor and shields (I have confirmed the latter in Skirmish against Bots). Of course, this kind of ability would normally be fairly-ineffective, the radius is, while fairly large, still not big enough to be a real threat to a wary foe, or even someone who just sails on through. That's where your control becomes hugely powerful.
With a couple concurrent shots of Eye of the Omnissiah, you can lock-down a small group of ships or a single big problem and drop a Rad-Tempest device right on them. Then, partway-in, you drop a Stasis Bomb on the enemy to trap them there for 20 more seconds. Done right, you can unleash an amount of pain that would make an Incubus blush and Inquisitors eye you warily, and with some fleets you can even follow-up with regular Nova shots to add yet more misery to misery.
The one drawback to both of these abilities is the fact that you have to enter medium ranges with your flagship in order to pull it off, which can put you at a significant risk of damage or even destruction of such a critical ship. The abilities have disparate cooldowns (Rad-Tempest has a very long cooldown), which means that you either have to pull your flagship back afterwards or be willing to take a large amount of pain in order to do it again, so your flagship really must be an Ark Mechanicus in order to pull this off.
I would argue that buffs that target the Mechanicus should somewhat reduce the cooldown on the Rad-Tempest Device, or increase its duration. The Device itself is fantastic, but the amount of pain you're required to take to use it and the amount of coordinated, limited-use Weapon Skills you have to coordinate to use it effectively really limit it currently. Tweaking-up the Health and Armor of the Ark would also help here.
Buffs targeting the Adeptus Mechanicus that I would propose would increase the base ranges on all their weapons. New Ships I would propose would include more versatile weapon-options or carry a ship-ability that improved the ship's tankiness (say, by increasing the armor of a ship and the minimum armor that a ship has after Armor Piercing is applied) at the expense of occupying the slot where a Torpedo, Spur, or Nova Cannon would normally go.
I would also argue for a rework to the Kastelan Robots upgrade to make it much more of a solid pick:
The inclusion of Kastelan Robots in a fleet's crew-at-arms increases the resistance of the fleet's Line Ships to Boarding, treating them as one step higher in quality when defending against a Boarding Action. In addition, the Flagship's Troop Quality is raised by one step.
This means that, at the expense of an upgrade, your troops will perform competently against Imperial and Chaos boarders, and your flagship also has a usable boarding option. It also helps with the feel of the upgrade: Kastelans are extremely durable and come with Datasmiths, but unlike Terminators, aren't very mobile. Making the Kastelan the "Admech Terminator" feels wrong, as Terminators are a different thing entirely.
I also wanted to touch on the "Static Discharge" Ability that Myridus suggested: on the Tabletop (40k, not Gothic), the Onager Dunecrawler gets the Emanatus Force Field ability, which is an Invul save that allows for rerolls when it is close to another Dunecrawler. A similar ability for their Line Ships would be fitting, then, say, one that boosts Shield Recharge and max Shields when two or more ships are in proximity, to a capped max boost at, say, 3 ships.
Finally, as an out-there, half-formed idea: Replace the Lightning Strike with the Mechadominator Ability (perhaps on a timer instead of permanent like the current one), and then give an Admiral Skill that targets a ship without shields and deals a critical damage to a random subsystem every X seconds.