I'm hoping they do a slimmer controller. I'm really enjoying Pikmin 3, but the pad is a bit too big and bulky for my liking. Something more like a Vita (with the shoulder grips) would be fantastic.
I don't think Nintendo were ready for what HD development required (look how off guard a lot of Japanese devs were in the early 360/PS3 days) and I think also then diverting resources to boost the 3DS library in 2011 meant that a lot of Wii U titles got far less resources than were needed for when the Wii U was due to launch.
I'm sure the software will be fantastic next year. I just wish I could say the same for the pad.