Like I've said already, it makes sense to hedge the ship models a bit to allow for the large ship battles that are a key component of the series. A large battle with ships of several thousand polys each would be unruly for even top-end systems. That said, most of the models in the game right now are quite nice even if they are poly-economical.
On the UI side of things, David Gervais' work always seems to be hit/miss with people around here - but you'd really find that anywhere. The key here again is that this time the complete interface is moddable - so maybe some enterprising artist will put some effort into an alternative UI for those players that would like something else. (Although I think it might weigh in at 50ish Mbs!)