I don't see why the wii u later years can't be its peak years. I still think the product re-packaged at the right price could do good numbers. Nintendo have lots of resources they could use to make the wii u an irresistible package. The main issue is that horrible over-sized gamepad. It's just not a good controller and doesn't feel good in your hands., I don't think the console itself has to change just the controller.
Let's not forget the console uses lower cost components than the 360 and PS3. The console is ultra cheap and there is no hard drive. The cost of the gamepad is probably the most damaging for both manufacturing costs and for damaging consumer appeal.