A feature requested by fans and ultimately denied for New Super Mario Bros. Wii was online multiplayer, which would have been a potential new way to get angry at your friends for stealing all of the stupid Ice Flowers when they clearly don't need more than one.
Official Nintendo Magazine UK asked series creator Shigeru Miyamoto if online multiplayer was ever in the cards or if it maybe was held back for technical limitations, to which Miyamoto replied with a big verbal shrug:
Well, it's not for purely technological issues that it wasn't included. After all, as you know, we already have online play in Smash Bros., and technologically speaking, I don't think it's creating a high amount of lag. It's just a matter of our priorities when it comes to the creation of a game. We just prioritised on making a multiplayer mode where four players can sit together and play while seeing each other's faces.
While we don't typically stare at each other's faces while trying to focus on the chaos at hand in NSMBWii, Nintendo did a bang-up job with the local multiplayer. But what about sequels and such?
We thought that [local multiplayer] was more important as far as this New Super Mario Bros. was concerned, but we don't know about the future. Because network environments are getting better and better every day, it may be possible in a future edition to incorporate that type of multiplayer online mode for a real-time action game. But I am just talking about the technological aspect here. What's more important, of course, is if it's going to add to the fun aspect of the game.
Throwing in some Wii Speak support and Mario Kart Wii's online feature set spells "winner" to us.