I think Nintendo could easily boost the Wii U's sales if they could make a Pokémon game that synchronises with an other 3DS Pokémon game. Why? The 3DS sells amazingly and if they were able to attract 3DS users to play with the Wii U to get more monsters and stuff..
Also they need those amazing titles like Zelda, Bayonetta, Metroid, F-Zero, Kirby, Kid Icarus, Galaxy, Star Fox Smash Bros, Mario Kart and maybe Mario Tennis, Party, Basketball or whatever.. I mean Nintendo has the best IPs ever!! They need to concentrate on them and release them as quick as possible.. I know, is hell of a money but hey!! It will most likely boost sales and also attract 3rd party companies who don't care about the Wii U now because they are scared too invest into the console..