Well, I have used Warp Pipe, and I try to play people online whenever I can. It's pretty good thus far. The speeds are ok as of now, I get like 20 - 30 fps, but then again its only a beta. It's pretty fun to play people online. And if they can get 55 - 60fps on Warp Pipe, then I will be happy.
Also, I think there isnt all that much profit in online gaming, at least not at this point in time. Right now its crucial for online games to be played on Broadband, 56k really can't handle games anymore. And right now not to many people have it. So if they decided to put let's say Double Dash Online. You are going to need a kid that gets the game, has a BBA, a broadband connection, and is willing to pay at the least $8.00 a month.
Nintendo's next console would be the perfect time to start to really consider online gaming, as I can see it to be much more profitable for them.