Oh gosh, I hate it when that happens. Lately the old wii remotes I used are becoming more glitchy. But the Gamepad... that's terrible. Mine hasn't given out - yet. And I hope it keeps a little longer.
Yeah the Wiimotes are glitchy too, mine were glitching on 1:1 motion games like Skyward Sword when I used it. Constantly having to unplug and plug the Nunchuck to stop Link running to the left. So Annoying. Some Wii games from Wii U VC allow for Gamepad use which is cool but they never implemented it for Skyward Sword.