I have been saying for a while Nintendo needs new studios. They don't need to make them. They should buy Sega, Capcom or some other developer.
They also need a new IP, hopefully we'll get one this generation. (X might be a new IP ... We don't know yet).
The human capital gained with such an investment would be fantastic. I do not know how they have not acquired Sega yet-if not for the IP alone. I mean, they were outsourcing some graphical development already (hopefully you know more about the specifics, I sure don't).
My theory is kinda Pachter like, and by that I mean obvious-Nintendo appears to focus on Japan first and foremost. Everything is then adopted to the other territories. Microsoft is 85% NA and 12% EU focused, (3% other) and Sony appears to 60% NA, 20% Japan, and 20% European. Sega appears to have tried to, unsuccessfully as a third party, become in line with MS and Sony.
Capcom on the other hand would be a great acquisition, but probably more costly. Ideally, both of those publishers, with their IP exclusive to Nintendo, would solve the majority of issues Nintendo has with attracting new customers. However, they would lose their independence, and we would probably see them assimilated to where they make fantastic games, but not enough of them on the console side to really make a difference.
Of the two, Sega would be the best managed acquisition with what Nintendo does. I would think the IP's alone would be worth it for both handhelds and consoles.
I would like to see them develop a 16-40 age bracket division, similar to how DC comics had Vertigo for adult titles (not a different umbrella, just a different goal of sorts). They could acquire developers, target 2 new IP's for the Wii U with the Bayonetta crowd in mind.
In either case, I would buy Nintendo stock now. I am very optimistic about their future, as E3 was just too quiet.