Interesting question.
IMO I think that Wii games are more "Games" than most of xbox360 or ps3 games.
I say that because most of non-Nintendo games are movie wannabes.
Just take a look where other than Nintendo gaming is going..
Games which their single player modes last for only 4 hours,with much of it being cutscenes..
Developers now pay huge money to cinema story writers,hollywood voice actors and musicians,and often overlook things like gameplay,replay value and fun.
Today's games feel more like interactive movies,while Nintendo's games like Mario or Donkey Kong feel more like Arcade games,the true and original that started it all.
Don't get me wrong,I'm not saying that one of them is good and the other is bad,it's just that the game industry has a schism.
I like playing both kinds of games.
I enjoyed the awesome cinematic feel Mass Effect and Crysis had,but I also love the gameplay at Nintendo's own games.
Will you believe it if I say that until I got Super Smash Bros Brawl and Mario kart wii,me and my friends where playing almost every week Mario Kart 64 on Nintendo 64 and Super Smash Bros mellee on gamecube ?
Games that are 10 years old or older?
Well it's true,and that's what's great about Nintendo games.
They never become stale or outdated and they are always fun to play.
I might question Nintendo's decisions regarding hardware,but I can only respect them as game developers because they make awesome games,that just doesn't loose their fun factor over time,which is something magnificent.
So Wii IS a gaming console.
Now regarding the future...
I speculate that most of the software developers will continue to try to make their games more cinematic,which means future games will have more cutscenes and will be shorter,while Nintendo will continue to create new things hardware-wise that we can't even imagine right now,and that Microsoft and Sony will follow Nintendo's moves on hardware.