GemRB should(?) get more attention. If it really is "Nearly feature-complete" it could kill things like Baldurs Gate Enhanced Edition without much hassle.
Baldur's Gate Enhanced Edition's scope doesn't end with the engine. It also uses better quality assets, AFAIR. gemrb should be capable to play it at some point.
About it being nearly feature complete, there are still some things to polish. Personally, I find it to be visually different (although that may have something to do with hardware blitting, I haven't tried software to double check, yet), and scrolling is certainly slower, although I think that's a matter of fine tuning, the engine itself (and that's according to the authors, too) could use some hardware acceleration. It's a great project, one I definitely think is worthy, but I don't think it's ready for prime time just yet.
Something that I really hate seeing in so many open-source games, especially RPGs, is when there is an inconsistency in art style. I'll admit that I have done this a lot, and I hate myself for it. It's why you need to have a team that can actually agree on a solid look. It's just so irksome looking at games and seeing people using pixel art sprites, but the interfaces are pixmaps or vector graphics with smooth edges and gradients, with true type fonts, that clash very strongly against the rest of the art in the game. It just feels out of place.
It's why I've started sticking to just doing pixel art for my games, interface and all, and leaving all my painting to just being hobby work.
Planeshift vote here, too. It has a unique playstyle, and while I didn't give it a enough time to learn it all, just the mechanics alone did keep me interested. It is a interpersonal roleplayer (like Ryzom I think it was, true to the spirit of an MMO), not your usual action-RPG you'll find nowadays. It was certainly a good game for a community effort and when I was playing it the low-level graphics issues had been sorted and the place was looking pretty sweet. A few issues with the interface being a wee bit clunky, but eh. I believe all RPG's have those 'unique issues'. Features.