FYI: AA costs the same as Hot Feet.
AA used to be the crown jewel of ice control. Now, with Cold Snap, Deep Sleep, and adaptive recharge it is less necessary, but its still good control. Put the contagious confusion proc in there for shiggles.
You can only have 3 arcs open at once (not missions). If you have 3 contacts that have the book icon then you can't get any more until you close at least 1 out.
Also, Dark Watcher requires you've completed the other 3 RWZ mission holders' arcs.
Tesla Cage has the benefit of
1. Allowing your blasts to grant stacks of Static
2. Doing some AoE damage when you have stacks of static
So its really worth it when paired with Electric Affinity.
You say its doable, even "100% doable" but this is going to be the sticking point.
NCSoft understood that the cat was out of the bag and there was no way they could prevent rogue servers from showing up. IMO they signed the agreement for 2 reasons. 1, I almost guarantee that part of the monthly donations goes into their coffers and 2. It gave them some free positive press. They're not going to let anyone make money off CoH though.
Concentrated Strike is hot poo. Either the animation time needs to be lowered or its base damage needs to be raised.
I'd love for Repulsing Torrent to actually do -damage like the rest of the set. It also should add a stack to power siphon when used (no idea why that got skipped).
Marine probably edges nature out, but both are very solid.
Marine has the advantage of being more offensive with White Cap, Tide Pool, and Shifting Tides
I think an Empathy defender would be way up there, and that's coming from someone who used to regularly solo his Empathy/Energy on Invincible (remember when that was the max difficulty?)
Sonic Resonance would be pretty high too, but at least it has the advantage of giving hold and stun protection to you.
Sentinels have slightly lower scalers than scrappers for defense/resistance but have the same caps (75% damage resistance, soft cap for defense is the same across all ATs). So they can be fairly sturdy if built that way.
Liquify got buffed a while back, its recharge got cut in half. I think it's in a pretty good place right now.
I used to think that the buff to liquefy was all that was needed for the set, but Marine has come out since then and it shows the devs are willing to give some extra "oomph" to support sets.
The biggest issue I currently see with Sonic Resonance is the endurance cost.
Dark servant, much like Seeker Drones is best summoned inside a spawn. Since it has Chill of the Night, you want it in melee range ASAP. Similarly, Seeker Drones makes an excellent alpha cracker.
An important thing hasn't been brought up yet, which is the biggest reason we won't see a COH2 any time soon.
NCSoft holds the license to CoH. They shut the original game down while it was still profitable because superhero games didn't fit their current vision.
Unless that changes (which us unlikely) or if they're willing to sell their rights to the game (equally unlikely) then CoH2 is a non-starter.