I actually hope it's on the same boat as the Wii based on third-party content. As I play every multiplatform game on PC, I'm not buying any next-gen console to play games that are cheaper and better on PC. I want a console that gives me smaller-budget third-party exclusives, like the Wii did.
About the multiplatform ports, Wii U has similar achitecture to PS4/NextBox, so it's just a question of lowering the graphical quality. The Wii situation was entirely different, as Wii was a single-core CPU/fixed function GPU console while 360 and PS3 were multi-core CPU/programmable shader GPU consoles, therefore, engines that worked on the Wii didn't worked on PS3/360 and vice versa. Wii U case is totally different, as every engine that works on PS4/NextBox should work on the Wii U.