Its harder to make a believable design because I have to learn some autonomy (without uncanny valley but with engineering common sense), even the textures are for purpose of make it look real. Its easy to imagine random mech because anything goes, that is not the case with sane design. If a believable tank wasn't hard enough, try design a believable plane. Not just believable but high tech future believable. I think the real beauty of mechs lay in the spirit that shaped the real ones.
Yeah, that's what I'm beginning to discover. I've been trying to study real military vehicles in preparation for trying to extrapolate some kind of future design (ie: different and futuristic, but feasible) it's been interesting. Hopefully I'll be able to do stuff on your level