This is a subjective matter that varies from person to person, some people think it failed while others think it was good.
For me, who was an exclusive Wii gamer for about 2 years after which I got the 360, I have to say the Wii did terribly this gen for the hardcore audience. With an abysmal third party support (all multiplatform games being far superior on the HD consoles), terrible online support in a generation where multiplayer has become the centrepiece, and gimmicky controls that are only fun for 5 minutes, many hardcore games didn't even bother using it entirely, eg, SSBB and NSMB, (a waggle doesn't count) while FPS games are just better played with the classic controller for better accuracy, eg, Goldeneye and Conduit. It may seem as though I am hating, but this is just how I feel. Once upon a time, I used to defend the Wii and blindly looked over all of its flaws, but only after playing on a HD console have I realised the major problems the Wii has.
That said, the Wii definitely won't be forgotten, as it has ushered in a new era into the gaming world (with new controls and bringing in the casual market) which will be remembered forever.