My favourite system is Labyrinth Lord (Moldvay/Cook D&D clone), but I still think C&C is closer to the OP's stated requirements. Using Washbourne's netbook PC classes in addition to the core classes gives a huge variety. The mechanics are simple and designed to be easily memorised.
BFRPG, like LL, uses saving -throw tables and Thief % charts, so cannot be memorised fully in the same manner as C&C. BFRPG has more class variety than LL, but much less than C&C.
OSRIC is a 1e clone, so it has the charts, and it has more complex rules than C&C.