ok so currently there are 5 classes of ship in the game. the rest are just variants and other cosmetic additions from the c-store.
a way to diversify ships would be to give the variants in each class different inherent stats to that ship.
example
tactical escort
defiant gets 15% base resistance to kinetic damage
variant1: gets 15% base increase to turn rate
variant2: gets 15% base increase to photon torpedo damage
something along those lines, doing something like that would give a reason to choose a different variant within a tier, and not change too much, (so as long as you do not add in some unbalanced out of proportion bonus)
heavy cruiser:
galaxy gets 15% bonus to engineering team skills
variant1: gets 15% bonus to hull hit points
variant2: blah blah
the bonus could be to a particular skill that that class of ship uses, like a science skill for a science ship or a bonus to the ship itself.
0