GalCiv's graphics are considerably better than MOO3's already, and have plenty of animations. Combining the two might make MOO3 a better game, but it wouldn't be doing any favors to GalCiv.
Felderin
New ship designs become available over time. Researching "Corvette Technology," for instance, allows you to build Corvettes. But you don't design ships in the MOO sense (in which you pick a hull and mount various components on it). GalCiv works more like Civilization, in which specific techs allow you to build specific units. Ship battles, by the same token, are also more like Civilization than like MOO. You move ships on the strategic map. Fleets are stacks of ships in the same space.
The graphics are quite good, really. Lots of ambient animations and a neat parallax effect with the starfield when scrolling the main view around. It's not an eye candy tour-de-force or anything, but it's clean and attractive. Sound is decent, but fairly basic. As good as any other turn-based grand strategy game, I guess. The music is nice.