Seem like you haven't met good arty. A single shot from arty can deal 8-12k damage with energy to weapon, with rapid fire it can shoot 6 consecutive shots in 6 seconds. Arty can basically melts everything from 7k range away and there's nothing you can do.
Tacts are vulnerable to a bunch of things because their movement speed is low (and they have no fire power so they have to hide, obviously). The easiest is tartarus that drain and disable everything, you can kill the helpless tacts after that.
Seem like you haven't met good tac cruiser. A single left click from tac cruiser can heal 3600 hp per sec with energy to weapon, with energy generators it can shield itself for 10s. Tac cruisers can basically heal everything from behind a wall and there's nothing you can do.
I'd like to point out that Aion's movespeed is 48 and has enough firepower to kill a corvette...Koschei just trades damage and movespeed for more healing. Even with everything disabled how do you kill them ? Shoot through walls ? My point is that tacs' gameplay is all about refusing combat and preventing their allies from dying because of their mistakes, which is very frustrating for the opposing team. In combat games, you get better by dying and understanding why you died.
Solution: just make every tac cruiser like the JA one, no healing, buff pulses, energy missiles, drain drones, etc...and more damage so they really belong in a combat game. More fun for everyone, even tac players (how is sitting behind a wall and left-clicking supposed to be funny).