I like the idea for torpedo bombers, but again it depends on the ability for incoming missiles to be shot down by ship weapons.
I don't really like the above stated role for interceptors. When I think of interceptors from reallife air forces, I think of large, fast, heavily armed fighters designed to quickly reach and destroy enemy bombers before they can launch their weapons. Being large, they tend to be less maneuverable than smaller general purpose fighters, and hence less capable in a close-up fighter dogfight.
There's nothing wrong with a class of fighters designed to take out incoming missiles and such, I just don't think that "interceptor" really says the right thing as a name.
good point, I too think of rather heavily armed fighters when I hear interceptors. I suppose someone could come up with a better name. what were those fast fighters called that you commanded a few missions in freespace 2 when you had to keep bombs from destroying a base? because that is where I got the idea from, looked a bit of what type of missions you had to perform there and what types of fighters were included and then thought what can be transfered to a strategy game.
a space superiority fighter is also heavily armed, isn't it?
one more possible type could be electronics fighters that carry either electronic bombs or according equipment and could hinder other ships functions. I is more likely something included for frigates and larger ships or an ability of a capships, but you could argue it for fighters because it needs proximity.
uh, yet even one more: a scanner fighter / ships. gives you an update on enemy ships' condition close by. needs to be balanced for how long they need to be in range and what kind of information you can derive from this, but it is an idea.
what you can maybe see is that my idea for differentiation among races also goes in different races using different ship classes for different specialist functions. one can use fighters for this recon thing, another a capship ability. helps making the races more distinct.