Nintendo does a lot of things differently than Sony and Microsoft.  Many of their actions, although questionable, are defensible by the Nintendo faithful.  
 
However, I do not see how anyone can defend their online system.  It completely detaches you from the experience of playing against real people.  I own Mario Kart Wii, and yes it is still an excellent experience, but it could be so much better.  For one thing, if I am in random mode and find someone I like playing against, because Nintendo does not allow any form of communication, not even written text, I cannot even get that person's friend code!  Of course, that may not be the case for ALL online games on the Wii, specifically EA games which have slightly more freedom, but Nintendo games that are capable of online play are definitely crippled.  
 
I hear the argument that some gamers do not want to be bothered hearing little 12 year olds curse on the headphones during a game like Mario Kart.  Well then, why not just make it an option to be able to turn off the headphones, so those that want to hear voices and feel the full online experience can enjoy talking to people, while those who do not like it can just hit the off button?  I believe that solution would satisfy everyone.  
 
At the very least, let us write some text on the screen so that we know we're talking to real people!  It's frustrating when the same track is picked over and over, possibly by new racers who have not realized that specific track was picked already.  Maybe with some form of online communication, racers can be convinced to pick a different course so that those who have already played Rainbow Road ten times in random worldwide mode can experience a new course. 
 
Just get friend codes online you say?  I thought the Wii is supposed to a streamlined experience though.  Yet, Nintendo makes it difficult by forcing gamers to search the internet for friend codes.  
 
My hope for the next generation is, that at the very least, Nintendo games like Mario Kart, Smash Bros., and all other Nintendo online capable games require only one friend code across the board for all games, so that someone on your friend list for Mario Kart will automatically be placed on your friend list for Smash Bros.  I mean really Nintendo, is someone I play Mario Kart against on a daily basis, suddenly perceived dangerous if I play the same person in Smash Bros.?  I hope Nintendo lets their guard down a bit in this subject, because although I seriously do love Mario games, I cannot stand Nintendo's convoluted way of setting up their online experience.    
 
I think they eventually will catch up.  Hopefully it will be in the next generation.