Oh, if anyone has ideas on how to handle things like curbs and stairs that would technically stop sliding collision but the player should be allowed to walk up them I would love to hear them.
You'll find that, with the built-in system, there's a certain amount of latitude dependant on the entity radius, the height of the obstacle and the speed of the collision. Simply put, you can already walk up stairs and small curbs - it's worth testing a few models out to get a feel of how large/small the steps you can get away with are.