Quoting myself from the mantis side re: multipliers, etc:
Yeah, that sort of fame system would be brilliant, actually -- it would play into a lot of the things we've wanted to do with the game for a long time, and would also serve to make it so that keeping a character indefinitely gets harder and harder.
With something like an endless runner (Canabalt, etc) your speed goes up as your score does, so it gets progressively harder to get the highest scores. That sort of feedback system is really important, I think.
That would let us build in a system of:
1. Named ranks for hero fame, as you noted (which people would love).
2. Extra monster agression and difficulty arising from increased fame (thus making death truly inevitable and keeping a character around for a really long time a tricky proposition -- and yet more reason for the Retirement scrolls mentioned elsewhere).
3. Some minor benefits from fame for your character, so that you feel more powerful and special from the fame even if the world is ganging up on you because of that fame.
That's a more complex system, but I think that's really worth it. That's something that is really striking me as a feature for 1.2 rather than 1.1, but it's going to be one of those changes-everything features for that version. Because then it really _would_ feed back into gameplay, in both positive and negative ways, and the fact that your actions matter get reinforced in a whole new way.