On the other hand (to play my own devil's advocate): I'm a huge T&T geek. The classic Fifth Edition rules are super easy, but the rule book is super long-winded (though enjoyable atmospheric and goes a long way to communicating the vibe of the game). The UK Corgi versions of the solos (two-in-one, in fact) have a wonderfully truncated version of the rules (about 16 digest-sized pages). It actually gives so much that one could actually use said rules for near-campaign-level group adventures, despite that it dispenses with many of the races and has only two character "types": warrior and wizard. That is certainly enough to start. That's absolutely and inarguably archetypal.
So, where might something like leave us?
Fighters and Magic-Users.
Cut down spell list (cut down levels? Five?)
Monster list taken down to the most archetypal and mythological.
Cut adventuring rules (traps, secret doors, travel, dungeon and wilderness distance, etc.) to the barest needed minimum?
Treasure list on a Holmes Basic level presentation.
Something like that.
Though...sheesh...I still worry about even more and more flavors of S&W alone that even it's (S&W) own flavors confuses just as much as each and every retro-clone in general already confuses folks... Heh.