I have read a lot of things lately on forums dealing with titans. The game REALLY NEEDS something powerful, I enjoyed playing mods having a supercapital or capitalships that were a bit powerful and expensive than the others. Entrenchment made a change in this situation, the powerful starbases were put in for defense purpose but still nothing for a deadly assault. Almost all sci-fi races have a supership so I think it's necessary for Sins to put some big thing into the game.
Titans? I'm assuming honestly that they are just the offensive version of a Star-Base. I don't think they're gonna be much - if at all - more powerful than a fully upgraded Star-Base. If a Star-Base is a nut, a Titan will probably just be the nutcracker.
I hope they will have (significantly) more firepower than starbases to fulfill the fleet destruction function but maybe less hull and shield points. But upgrading them is a question. But it would be great to research abilities for them, 4 or 5 and if the research is finished your titan will be able to use it immediately (thus no need for further purchase like on starbases or to get experience points like on capships), or having many abilities from which you have to choose some.
Titans, what would be the approppriate number of them? Or is any limitation needed? I think yes, maybe a limit of 3 or 5 would be acceptable (although we can just guess their stats...), maybe if they are strong enough let a player build just one with wonderful abilities and power.
Titans run the risk of invalidating all previous content... making Star-Bases and the Super-Cannons largely irrelevant. It's going to be tricky balancing this.
I think we shouldn't worry about this, because Rebellion is said to change much things, and I hope they will rebalance the role of all now existing ship types (for example to evade the situation where capships will be units you don't want to build because you have a Titan or etc).
I don't agree with you about starbases, I think there are no huge changes needed, they are excellent defense units the way they are now. If they change the overpriced or useless ugrades (Colony pod- my heart hurts for it because it would be an excellent idea but whith this small population no, and the Induced Reverence needs to be more powerful)
I agree with you about superweapons. Even in Diplomacy I don't build them very often because I don't think they worth their price, but I think they will be changed somewhat to fulfill the Real Super Weapon (but immobile structure) role.