This is as general as it gets, and yet I haven't found any clear guidelines in any of the guides I've read. Even for the most basic deck archetypes -- aggro, midrange, and control -- the most I've seen is "Ideally, you want enough cards at each mana point to have a good chance of having a minion and spell in hand when that mana point comes up." Reasonable advice as far as it goes, but it doesn't go very far!
Obviously lots of things can affect the ideal mana curves -- hero choice, the metagame, specific cards in your collection -- but if you had to recommend a platonic ideal curve for each
