TEC:
Mobile Novalith...one shot kills planet..regardless of Aux Government/ fun to hunt and find.....
Advent:
Mobile massive culture center you move into a enemy well...takes over the enemy planet immediately and 3 surrounding planets.
Vasari:
Move your entire fleet at once to any well....very long..very long...cooldown.......
Almost like "Wonders" from other games.....Maybe Sins 2 ideas........
I'd say reconsider these things as changes to the superweapons instead of changes/modifications/additions to the titans...
Nova kills planet using make dead instant action (bypasses auxilary gov, just like wail) and prevents it from being colonized for x minutes....
DE captures planet and spawns culture (temporary economic debuffs should apply to the planet to balance this with nova)...
Kostura uses make dead instant action on all structure, spawns phase node...
Course, you'd want to increase the cost of superweapons (and adjust cooldowns as necessary) but at least they'd be true game changers....