I think we can all agree that Friend Codes suck.
I also think we can all agree that, if we're stuck with Friend Codes, the way Mario Kart Wii handles them is about the best we're going to get.
With this in mind, I would like to propose a new Wii Channel: The Friend Code Manager.
This channel will automatically pull your Wii Friend Codes from the save files on your Wii and store/edit them, allowing you to trade FC's and register FC's from existing WiFi Games with any other Wii owner who has this channel and you've already traded Wii System Codes with (similar to the Mario Kart channel).
Additionally, you can register your existing library of DS WiFi games and use the Friend Code Manager WiiWare to send automated messages to your friend's Wii's inviting them to add you to their DS game. (It'd be awesome if there was some way to automate this process by linking your DS to your Wii like Pokémon: Battle Revolution or something, but that's probably asking way too much).
Now, in a dream world, the Friend Code Manager would also have a Pictochat like program, allowing you to chat IN REAL TIME with anyone (or any group) of people who you've exchanged Wii System Friend Codes with. (WiiSpeak?)
And what's better is that the Wii Friend Code Manager could, ideally, be tied into Nintendo's NintendoWiFi.com and know what game you playing online right at that moment on your Wii or DS... and would know what games your friends are playing online!
Now, this isn't a perfect solution, as you'd have to have this WiiWare application loaded to see who's online/what they're playing, so if you're playing Mario Galaxy, you won't get a message saying your friend just hopped onto Mario Kart... But if you're in there chatting with friends, you'll have the chance to see someone pop online.
Imagine having your Wii on and in the Friend Code Manager. You could have your TV on a different channel or be in a nearby room and your Wii Remote could "ring", letting you know someone has popped online.
And, finally, you can use this magic channel to play DS games that use Local Multi-Player against friends anywhere.
Yeah, I'm dreaming.... so what?