Thanks for the answer
Then PolyVox it shall be.
I guess I could still look at Thermite to get an idea of how I can combine PolyVox with Ogre (and Bullet, while I'm at it).
Yeah, it will definitely be a pretty nice learning experience. Unfortunately, I won't be able to really start anything until next year. But I will spend what time I have right now to continue my research on libraries and planning.
Already have possible solutions for most issues. The biggest one remains that I want the project to be multiplatform, at least in theory, for Win, Mac and Linux (or only two of those, if it must be). That, and networking.
When I reach the point to have anything to show, I'll do it here, for sure. And an army of robots fighting an army of ogres would already be something to show, I guess