Realm Zero has your number, and not coincidentally, it just entered its second phase of alpha testing. No, really, it's not just a collection of concept art! There's a video past the break and everything. So if you're leery of giving your heart to a game that's a bunch of lovely ideas with no actual game, well, at least that's not quite what's happening here.
The game promises to have an evolving world based on player action, with combat based upon FPS models rather than on the traditional level-based grind of most MMOs. It also boasts a skill system that allows you to build a character without having to make permanent choices, so you can mix and match over time to build your preferred character. Read more on the official site.
[Thanks to Sandboxer for the tip!]