Well, WoWs character customization and options are really low. If i remember right, they removed the complex talent system because they argued with the availability of cookie cutter builds, which would make options none existing.
If you think about it, even with the small number of options there still are cookie cutter builds.
Which means, that in consequence the level of complexity has nothing to do with the fact many people will just copy paste a talent build from their favourite web page.
Which means, that blizzard could also add a way more complex system to give character depth and a possibility to make characters more unique outside of the idea to make it perform most.
And in general, blizzard should think about the idea to disencourage performance as the only means of valid talent builds. Which could be achieved by a degree of horizontal progression, based on giving rewards that help you on your own subjective playstyle. As like having special gear and talents for dungeons, as like having special gear and talents for pvp, for damage dealing, for healing which would allow a myriad of combinations instead of just .. 7.. based on the spec.
Blizzards argument to reduce the number of talents has proven void, so the consequence should be to add a talent system 3.0, the removal of specs and the free choice of skills you could use for your very own playstyle.