User blog comment:Ironreaper/Retcons and Contradictions in the Reapers/@comment-3097746-20120419032849/@comment-1388547-20120419051851

I can see the destroyers looking the same -- they're made from the "trash" races that weren't good enough to go into a capital ship, so perhaps they're just mass-produced according to a standard design, with no acknowledgement of the individual race that formed the raw material. I would have preferred it if the capital ships had some variety in appearance, though. Perhaps it is just a matter of game resources? The scene at the end of ME2 had some bits aboard the trashed Normandy, but the part with the Reapers themselves had *only* Reapers -- no quarian, turian, asari, human, etc. ships like were present in the ME3 fleet battles. Perhaps they weren't able/didn't want to display so many models at once? (Or perhaps they were just being lazy or cutting costs.)

The Normandy might plausibly engage a single Reaper destroyer and win -- we don't have any direct player experience with space combat that would allow us to say. The destroyers are only, what, 160 meters long, and at a rough guess the Normandy SR-2 is over 100, so she's not obviously outclassed. Against a capital ship, of course, the Normandy has no viable option but to run away.

If I recall the description of the battle over Palaven correctly, the turians did manage to kill a few Reapers. It cost them a big chunk of their fleet to do it, but they demonstrated that, through surprise, skillful maneuvering, and several ships ganging up on a single target, organic-built dreadnoughts could destroy Reaper capital ships.