I'm not a fan of the Path of Exiles skill tree, but I was so incredibly bored with Diablo 3s skills. There was literally no choices, just switch whenever you want something else. I don't think the skill trees from diablo 2 were too complicated to expect an RPG player to manage.

To me the skill tree in Diablo 3 was saying "our player base is too dumb to make a single character choice, so we'll just get rid of all choices except 'number go up' when looking at new gear". It was absolutely a dumbing down.