I think the graphic look used in BG2, IWD2 or PST would be fine. It was all marvelously drawn and colorized for a very rich and textured feel, but it didn't feel like a photo, it felt like a very detailed adventure book so I think this is the best approach, even if this were to be a Sci-Fi themed cRPG.
Now, this doesn't mean all should be as still as it was back then. I like my old cRPG's to look like a beautiful water-paint but not to feel like one; even back then I missed some more animated elements, some vehicles, some really big creatures, sea waves, and a not so static nature in general. They talked about this during development of BG2 but I saw just a few of these elements at the city of Amn. With IWD2 we had a bit more of those animated elements, but still they were ocasional.
To be completely honest, I think Project Eternity should be set in a Sci-Fi environment, because the market is over-flooded with Dark-Ages' style RPGs while there is A LOT to explore in an isometric Sci-Fi environment both visually and gameplay-wise.
But I understand a setting like this would be too much of a risk to get the funds for.