Hey!
Those are some nice looking ships there

I personally like the last "arrow" one
As for making unique ships per faction - why not go third way... Make all ships that are "baseline" to be shared. So every faction will have "base" variant of starting ships (I do not know how you want to handle that, but every game has most baisic starting units that do not require ANY research unlock), but as they research more advanced ships, they start to diffrentiate more and more? Maybe simple example as to what I have in mind...
Faction X and Faction Y start game with ability to build:
- baisic frigates
- baisic destroyers
- baisic cruisers
All those ships are shared betwen those two factions. However as soon as those factions reserach better versions of those, they got unique model that will fit their faction. So baseline is the same across whole race (in this case Humans). But as game progress, diffrientation becomes more and more apparent. And those diffrences do not need to be actually huge. They may be visual only even... Though I personally preffer to see real diffrences follow with visual ones (for example if faction X is supposed to have better shields than faction Y, insted of giving it flat +10% bonus to shields, I would preffer their ships to have 1 additional place for shield module, that can not accept any other type of module).
But that is just my take on this situation! I am not even sure if it would fit at all!
