IMO, I think anti structure frigates should be able to attack Titans. Titans need some weakness. It is too easy to make a Titan early, then send it to someone else's planet and let it nuke the planet.
Still, if you don't like the idea, then I'd recommend the Titan as a level 8 research as an alternative.
What do you think?
And by the way:
Two things about the Titan:
1: Bigger. Need to increase the overall size of the Titans. A light frigate should be able to fit neatly inside a Titan.
2: The Titans are just too fast. They can go as fast as a KOL. It should be (at the minimum) around the Vasari star base speed.
