I got the Wii around the same time as World of Warcraft.
If it were not for WoW, I would be playing with my Wii contantly.
That said, you can't complain about the quality of Nintendo-made games.
Now 3rd party games on Wii are mostly crap. Don't blame Nintendo, blame the developers who don't put in the time to learn to use it's unique gpu.
Factor 5 being one of the exceptions to the rule. Capcom being another (Resident Evil 4 FTW).
Factor 5 is Wii-making the Rogue Squadron series from the Gamecube for the Wii. Maybe they'll put Turrican in there as an easter egg. Also they are rumored to be developing a Kid Icarus game, reviving it from the NES to the Wii.
If you want a challenging Wii game, get Metroid Prime 3.