GTA/Rockstar rumor was spread before the Wii was revealed as well... this is nothing new. Probably none of these rumors are true.
If I was Nintendo, I wouldn't even put out another console for the next 3-5 years. They really just need to make some good games for it, i.e., games the market wants to play. They can start with Making a proper, full-budget 2D Mario... That will sell another 10 million Wiis. STOP making 3D Mario, the market overwhelmingly does not want that type of game - sales prove that but Nintendo wants to force it on people with Tutorial DVDs. Zelda has become lackluster and sappy... Go back to the original Zelda formula (drop the puzzle-quests and NPC interaction crap) that started the craze (Action/Adventure). Add some new innovative IPs... does anyone remember all the crazy games that came out for the NES? Much more interesting, fun, and social than games today... but they weren't labeled "casual".
Companies like Squenix need to take a break on this FF garbage they've been rolling out and go back to their roots... all these game companies lost their magic as the transition from graphic-intensive games and 3D evolved - they are too focused on flashy cut-scenes and not focused on making great games. Mass-market games don't have to be WiiSports. SMB was a mass-market game but "hardcore" as well, so was the original Zelda.
There is no such thing as casual/hardcore games, there are good games and bad games, its just that most games today are crap since developers lost focus. Game-making is a lost art.
If Nintendo would just go back to its arcade roots, they could clean house with Wii for a long time... at least another 3 years. There is no need for all this better than PS3/Xbox nonsense. Its all about the games. These other companies aren't even making money this generation, that isn't going to change with a system with better graphics. They need to learn the lesson of loosing their asses on their highly marketed, over-budgeted, paid-off reviewed junk and learn how to make a great game with limited resources, both financially and graphically - then they can move on to bigger and better.
Most can't even afford nor wants to buy a completely new console.