I think if I were to design a pure point build system for WoW, I’d probably base it on the original talent tree system. Only instead of three trees (or four), a character would have access to six, each one based on the Warcraft cosmology system: Arcane, Death, Fel, Holy, Life, and Shadow.
Or just go with three generic trees: tank/dps/heal, or melee/range/magic. Whatever.
In any case, each tree would have a whole bunch of passive and active abilities and spells to choose from. Access to more powerful abilities is gated by putting in a requisite amount of points into lesser abilities in the same tree first. Which is justified by the fact that skills don’t exist in a vacuum; learning more powerful abilities is based on a foundation of learning lesser skills first. You can’t write long winded posts without first learning to read after all. 
A player is encouraged to put most of their points into a single tree, because the most powerful abilities are of course at the very end of that tree. But they’re also given just enough points that it’s worthwhile to put a few points into one or two other trees. A character’s “class” is more or less determined by what trees they put points into and what trees they prioritized.
Ideally, there’s no wrong way to play and any build would be viable… but I’m pretty sure that in actual practice, I’d still wind up with cookie cutter builds. And the only hallmark of a well balanced point build system is that there’d be more than one cookie cutter build that’s considered viable for a given role.