Try this game:
Tell WOTC how to renew their settings for 5th Edition in two sentences or less. You have to do at least three settings. Extra points if it seems like something they might actually do.
Here are mine... Dragonlance
Still a high-fantasy adventure path--but gamify the players' attempt to stay on the path and play their character: each player gets an objective slipped to them secretly ("Kill at least four draconians before reaching Mindenhork") and they level up when they achieve the objectives--at which point they get a new one. Also subsidiary objectives worth xp--but monsters alone are worth little or nothing.
Kara Tur/Oriental Adventures
All the Kara Tur classes are feat-heavy 4e-style variants on the core classes. Lots of shoving people around the scenery, tactical combat and crazy stunts and all the feats have names like "Thousand Golden Mantis Lock".
There's no good reason not to just release Dark Sun as a complete Carcosa-style hexcrawl from the get-go, accompanied by random tables (like these) for generating weird locals and villages. Without these details, the setting can be summed up in like 4 pictures and there's no need for most of what's in the boxed set.
…is redone as essentially Call of Cthulhu Medieval. Or the Dark Country. Ravenloft itself is just a big gothic country or alternate earth but the characters start out as Old School-style useless 0-level funnel-fodder in a place with terrible communication and supply lines and have to scrabble and scrimp for class features and spells.
Start by releasing it not as a standard setting book but as an alternate monster manual--with each standard creature rewritten--with no stats (or collapsed stats) but with info on how they fit into the politics and ecology of Eberron.