I'll use D&D as the example since it's a common frame of reference. As you move into HL play I would expect more interaction with the wider world as the threats at those levels tend more often to be world shaking and the impact of the PCs on the setting is high. The higher the tier the less actual monsters are around to reasonably challenge the PCs on an X encounters per day level, so the action needs to shift somewhere. Obviously this will look different from table to table, but some mix of politics, strongholds and followers, major factions, and major exploration would be my expectation. The HL abilities of the PCs need to be met with appropriate challenges, however that's handled, but it probably won't be a steady diet of dungeon crawls, although that is possible.I should have been more explicit - what do you expect from the system (which inludes mechanics but also thing like monster manuals and such) for high level play.