Ignoring skill and the differences between ships... it's pretty much already like that.
Also, you can't just say "Fighter" Because there are four classes of fighter. 1 VHF = 1 VHF, but 1 LF = 2 VHF for example (may not nessisarily be true)
There are also several classes of Crusier, which include Crusiers, Destroyers and Battlecrusiers. 1 Battlecruiser = 2 Cruisers, stuff like that.
Then you also have to consider Bomber vs Cruisers and Battleships.
I think each ship needs to be balanced individually instead of together as a group. Our ships vary greatly from faction to faction. One Liberator can easily take out 4 Werewolves, but one Hyena is going to have difficulty taking out 4 Guardians.