Reading the most recent News Post from Tycho at Penny Arcade (http://www.penny-arcade.com/news/post/2015/08/05/) when I noticed him talking about a game called “Galax-Z” and how you are only allowed to “save” when you complete a complete 5 level “season”. When you break it down, this is what games like Spelunky are doing with the tunnel man system, or as Tycho points out, as From Software is doing in Dark Souls with the bonfire mechanic. You can have players run though your procedural system many times getting better, and have a strict cap on the amount of in game “progress” they make that the game keeps track of.
In this way, maybe its possible to avoid the problems inherent to a regular RPG level up or upgrade system (emphasizing grinding over skill improvement, which is boring), while retaining a bit of their stickiness factor.
Even Ori and the Blind Forest has been playing around with saving as a limited resource lately, and I think this is a very interesting design direction to take.