These all sound great (except for (4) -- I think this mirrors the underlying reality and is good), but I'm not sure if any would be killer features. One thing

These all sound great (except for (4) -- I think this mirrors the underlying reality and is good), but I'm not sure if any would be killer features. One thing I think would be a killer feature (though I'm not even sure if it's possible): Supporting large binary assets in the repo without slowly down terribly. I'm pretty sure that would be enough to get many people to switch. From there, you might see a network effect as people that didn't even care about that grew to like your other points of improvement, and eventually Fossil could overthrow git and becoming the reigning VC champion. My 2¢. ;-)