Raze, 2 things.
1. Developers demanded the attachment. They weren't happy with just a wand and knew via Wii development that you need an analog stick and a few buttons to go with it to make it a viable input method for complex gameplay. The use of the Duals shock 3 was the interim fix but the idea was scrapped because it was bulky and prone to flying out of developers hands when swung. They eventually conceded to include a nun-chuck like device.
2. Nintendo owns patents, true, but you can only patent a method of something. You can't patent the overall idea. And beyond that, you only need to alter a few things to bypass the patent completely. Take rumble for instance. Nintendo owns the patent to the rumble technology in the controllers yet Sony has rumble in theirs. But Nintendo couldn't sue them because the design was different. Ironically, Immersion Corp had a vibration patent that was exactly like the one Sony used in their controllers so they did sue.
The rEVOLution is not being televised
