At the end of our old campaign, characters had reached 11th level. Many had already multi-classed. Many players found fun to "open" as many skills as needed. Main skills were not often developped to the cap, ie. beyond 20 ranks.
Main issue for high level chars seemed to be: what the hell can I do with my DPs? So the idea was to provide incentives to develop skills to the max possible ranks, create more talents, and of course multi-classing options.
High level chars need a separate book with heroic and beyond career paths, imho.
As the GM, I was thinking about including advanced skills options, à la Martial Law "Scaled Combat Actions" (p23-old version). Some simple and quick ideas were to let a very highly skilled character move fast while hiding, or climb unusual surfaces. Some skills were much harder to "scale up". Going "super heroic" and beyond normal use of the skill was the goal. Someone on the board sent me a very good spreadsheet with many ideas (Pat, maybe?), I just had to put them into place when we stopped the game