I don't find the absence of visible turret mountings on the sprites to be any problem. Seriously, that's cool with me; kinda liberating, in a way.
Interesting bio-mechanical hybrid look to these ships; more of the same look, please.
The Rodope frigate is a bit light on detail and texture. I don't mean the absence of turrets, though -- those relatively large areas of cream/white hull need some more color variation, or perhaps some greebling. Or both?
Hull perimeters are mildly spoiled by some minor jaggies. No big crisis, but distracting.
Overall, I enjoy what you've done and am eager to see more. Definitely a good reaction.