For real, though, here's where I'd go with it:
First, NO DMG. Why? Read on.
1) PHB: Mashup of 5E, 4E, 13th Age, and Shadow of the Demon Lord. It would use 5E's bounded accuracy, advantage/disadvantage, and cap on overall complexity. From 4E it would take powers, power sources, healing surges. Not all classes would follow AEDU, but I think that's a sturdy framework to start from. Shadow of the Demon Lord would influence the class structure. Something like novice/expert/master paths or base class plus paragon path and epic destiny. Like 13th Age, it would substitute skills for background and put an emphasis on narrative mechanics. Also: abstract distances--far, near, engaged.
2) Monster Manual. Definitely take inspiration from 4E and 13th Age.
3) Campaign Setting based on 4E's Points of Light/World Axis. I'm not a fan of the Nentir Vale. It's a rather dull expression of a really wild setting. I want something that feels like you're adventuring through the epic ruins of a broken cosmos!