The auto-save code has been updated and works much better now. That was the first step in getting the manual saves working - but they aren't quite ready yet. Working on staggered saves + save slots, no ETA at the moment though, sorry.
Edit: Actually, I'll be a little more specific. Staggered autosaves + save slots are probably out this month. Manual saves are quite a ways off because they break a lot of stuff in game right now. I'll need to set aside quite a bit of time to get them working, and it's one thing in the pile that needs to get done.