I like the big four for races: Human, Elf, Dwarf, Halfling.
But only four classes seems too few for me. Even if it is the very basics. For classes I would go with 8 classics:
Fighter, Wizard, Rogue, Cleric, Druid, Ranger, Bard, Paladin
It's just not D&D if we don't have alignment arguments about paladins.
Though honestly, I might prefer to substitute Warlord for the Druid. I think the Warlord is a very strong intitial class, and an inclusive edition should include some things from 4E. But the Warlord, or any non-magical healer, is a pretty controversial class.
But only four classes seems too few for me. Even if it is the very basics. For classes I would go with 8 classics:
Fighter, Wizard, Rogue, Cleric, Druid, Ranger, Bard, Paladin
It's just not D&D if we don't have alignment arguments about paladins.

Though honestly, I might prefer to substitute Warlord for the Druid. I think the Warlord is a very strong intitial class, and an inclusive edition should include some things from 4E. But the Warlord, or any non-magical healer, is a pretty controversial class.