While I do like the idea and did enjoy this back when I played EQ, you are really opening up Pandora's box.

It won't take long before the better players find the path/skill set that is most OP and soon everyone is just another carbon copy of each other. The game is pretty well balanced as is right now, and adding new skills/spells just makes it that much harder to stay balanced.

Generally you end up with much more QQ'ing about spec A being so OP that it gets nerfed resulting in QQ'ing for respects. It is very hard to give players multiple options without one being the clear cut "best path".

I think there is a lot more for them to work on before they decide to undertake something like this.