I have just finished WE grand campaign (Orion) on very hard and i think WE are balanced. They play fairly differently then other races but once you embrace that they are not that hard.
I realized once i trade enemy settlements with my outposts i can win pretty much any war. Just run in with all my armies and rampage enemy teritory(allways seed). What you lose by losing one outpost is waaay less than what enemy loses by losing one settlemet and so you basically dont fight directly, but more like war of attrition.
I believe wood elves are gread and balanced, only underwhelming unit in the rooster is the dragon, but then, so are all dragons in game...
I think WE are misunderstood and weak if you play them as you would play traditional Total War faction (like Empire or Dwarves for example).