I see no option of adding a super tanker for the next release or two.
As for weapons, Nova power will be reduced, but not much. There will also be changes about current capital ship weapons: I will be adding new weapons for capital ships, and you'll no longer be able to reduce cost of ship 2-3x by stripping it from turrets.
Tizona del Cid will overcome some changes: level 9 version will have less power, but there will be a new level 10 version that will deal more damage than current Tizona. A Tizona turret (level 9) will also be available.
Shields for all capital ships will become tougher, but their type will remain the same. Red Hessian weapons deal much damage to graviton shields, that's well known fact - but that's also how it should be. Fear Hessians.