I see this a lot: "Well, X should have been part of the Core Books in D&D", or "They can dump that, I never saw it as a core part of Dungeons & Dragons".
So what would be "core" (vital, necessary, needed, desired) for your ideal edition of D&D? Hit Points? Vancian magic? Classes? Gnomes, elves, halflings, bards, monks, rangers, half-orcs? Perhaps all you need is 3 basic classes and a star to sail 'em by? What would you miss if they took it out of the 3 D&D core books (or the core books of your preferred edition)? Or is there already something missing from a more recent edition you feel should have stayed in?
(Honestly, I'm the only person I know who really liked playing gnome bards, so I'm just going to bow out right now and await the comments below...)