Your example is not silly at all, and it is in fact something I've been trying to do *in addition* to other ways to extend the end game. Tiered content is great–but it's an ongoing, endless process. During which I like to use shortcuts wherever I see them. I think mixing and matching content and mode is the best way to get maximum mileage.

A "hard" mode doesn't have to be "dumb"–it can in fact be tied in with different ways to experience the same content. For instance, I'm a big believer in well-defined classes, because they multiply the ways one can accomplish the same goals. The same can be said for a good implementation of "normal" vs. "hard" mode. In your example, you could make the ogre mobile if fought in "hard" mode, which would make it more challenging to keep it in the room above the treasure room. Then, you could reward the player with a better treasure for having pulled it off.

I prefer Runter ways. The mobs is not harder to kill by an arbitrary level change just because you are higher level, but by they way you kill him allowing to pound the ground so he reveals another items that was hidden through some crack in a wall or something.