Once you start talking cool downs, or mana pools, you are no longer talking non MMO D & D. Not any version. Not any permutation. Not any mutated variant.
Period. End discussion.
You are indeed talking about an MMO like EQ or WoW or D & D On-Line, or a game such as DA or Diablo. All fine games, but they are not D & D.
Whether it's BG or IWD or even newer games such as Pathfinder or Solasta, there are NO cooldowns and no mana pools.