Ports between WiiU and PS4/X3OX is going to be much easier than ports between WiiU and PS360. Yes, CPU's different architecture, but they all use "out of order" processing. So no problem with ports there. (PS360 CPU's used multhithreaded processing, so became an issue for quick WiiU ports in the beginning.)
WiiU, PS4, X3OX all use GCN architecture as far as GPU's go. So no problem with ports there, either. Everything is going to scale easy and effortlessly. It will be NOTHING like the original Wii/PS360 ports. So forget that. It's not going to be an issue.
What is going to be an issue is 3rd party titles not selling on WiiU. So. If Watchdogs/Splinter Cell/Assassins Creed 4/Rayman Legends ALL fail to sell on WiiU. Then, and only then can WiiU owners forget about 3rd party support starting next year.
Essay Pro