If 4E were a big success, one would expect the game's continuing evolution to build on those changes.
Whether or not 4e were a big success, one would expect the game's continuing evolution to reach for market share the current game doesn't already have, broadening appeal, rather than focusing and narrowing.
The real evolution of the game isn't in the fancy classes and races, but in the mechanics underlying those races and classes. Rebuilding the old tropes in the new framework is building on those changes, with an eye to selling to folks who aren't well served by dragonborn, tieflings, and shardminds.