Big ships are able to fire on fighters and bombers, but to strengthen the role of the corvettes, they hit nearly nothing.

And your argument with the Hatak shooting down the X-303, well, that is tactics! If you have a lot of bombers and shoot down the enemie's possibility to kill them, then congratulations, you are the better commander!

Concerning Atlantis: it's still not decided how we will build it in, but i think you will not need the 3 ZPMs...