i don't think Nintendo will actually make mediocre wiimotes. PS2 has had that problem because they make easy to break stuff at the expense of cutting edge technology. I know this as I was at a friend's place and we were playing a PS2 game and he pulled the controller and the console fell to the floor after a half meter drop and literally fell apart! He did the same thing with the GC and it didn't break at all or anything - just fell and we still could play the game on the screen as if nothing happened lol.
Nintendo always thinks about what would happen with their stuff - by the way they would think about crazy kids who would throw the wiimote at a wall because they got too carried away with an intense game. I've never had any problems with any of the nintendo consoles (except for worn out N64 joysticks) and I often am very rough with the controllers.