It seems to me that there are two different paths you could take if you wanted to develop 4e. You could--and let's be honest, probably should--lean into its identity as a small-scale wargame, and focus on streamlining and balance and such. But there's also a temptation to say "I like the AEDU power structure and healing surges and tight math, but the existing powers are too narrowly focused" and try to create something more like "classic" D&D. Which would be an interesting exercise in game design, but wouldn't have much appeal to existing 4e fans.