So are we saying that the textures need to be bigger? I'm not sure what else I could do to them... As for the models, I guess I put in as much detail as I want to UV map. I suppose the lod's could probably use more detail.
Speaking strictly as an outsider, and not really knowing what methods you used (unique mapped? tiled?). Let's take your marauder as an example - texture wise, it looks like a great start; a base for a texture. What it could use is a lot more greebling, machinery, that sort of detail. It could also use baked occlusion (doesn't work with tiling, mind you), lights when applicable, etc. And, for a star wars ship, it could definitely use a lot more weathering. Don't get me wrong, what you're doing is good work, but the textures could really stand to be spent more time on being detailed.
Basically, just put it next to something brand-x has already fully textured and you'll get the idea
As for the texture sizes and count, I have no idea what they are on your ships currently so that's a bit tough to answer.