Agreed. Relating that to my favourite version of D&D - 4e D&D - the difference between invokers and wizards in that system is almost purely an artefact of the stat system (WIS vs INT) which is then overlaid with a rather arbitrary distinction between Divine magic (which invokers wield even though they are not priests or servants of any particular god) and Arcane magic.I think that Tolkien, for example, would be appalled that D&D's wizard, which is modeled after Gandalf, Merlin, and other magical characters, would be defined by their Intelligence rather than say their Wisdom, which was often the hallmark characteristic for these sagely figures. They were meant to be the source of wisdom.
Within the context of the game it works - but the difference between an invoker and a wizard is just about the least profound setting element of 4e D&D. The difference between a STR paladin and a STR cleric is next-most in this respect.
In AD&D, a paladin and a druid both need CHA, but a cleric doesn't. Why? Almost entirely that sub-classes (i) can have arbitrarily higher stat requirements compared to principal classes, and (ii) sub-classes are allowed to have a bit more quirky flavour than principal classes. But there's nothing inherent about the divinely-inspired heavy armour wielding warrior that makes CHA more or less central to the paladin instantiation compared to the cleric instantiation; nor about the conduit between mortal and divine/supernatural that makes CHA more or less central to the druidic/animistic instantiation compared to the to the clerical/Abrahamic instantiation.