But that only goes so far. Some of the key combination do have a nice mneumonic attached to it. But it definetly can't scale. ZZ is one of those, which is the case with most key combinations :/
My experience someone somewhere generally has a mnemonic for even the weirdest vim key combinations. Even ZZ probably has a mnemonic at least one person uses. Mnemonics sometimes have a lot of brains to scale on.