Well they won't make it over. Plain and simple.
Of course games like Watch Dogs are coming to Wii U but that game was developed with current-gen console limitations in mind.
In a few years we'll be seeing massive open world games that will just be impossible to port to the Wii U due to technical limitations from all angles.
Call of Duty isn't a good example as that is essentially a sports game. It's not very technically demanding and they haven't exactly pushed console limits. I don't expect many games to limit themselves just to be able to release on Wii U. Of course, iwth a lot of sacrifices I'm sure many games will be able to be ported down. It's actually kind of amazing that MW3 got ported to the Wii.