So back to Basic/Expert and AD&D? No thanks. And in a sense it already exists in the form of the Starter Set/Basic Rules, as AlViking noted.
Nah. The Basic Rules for 5.5 are still 5.5. Weapon Masteries, Starter Feats, etc - it's all still there. Just fewer subclasses.
Heroes of the Borderlands isn't at all what I want in a D&D experience, although Welcome to the Hellfire Club is closer. But regardless, Starter Sets are aimed at new players with the ultimate goal of moving them into the main 5.5 product line. I'm not talking about a product for new players specifically.
My suggestion is that WotC might want to consider why indie publishers offering simpler - but complete - iterations of 5E are doing so well, and maybe pursue that market in a low-risk way.






