At first glance the consoles all seem the same in the aspect of how the game is played. Having played all of the Skylander games, and having Superchargers on more then one console. The Wii U version has the full experience of Superchargers.
I want to stress that if you are limited to one console and it's not for the Wii U that is alright also.
I just wanted to point out that too much is missing beyond just having 2 characters, with upgrade trees. You end up missing out on the other half, which is everything that the exclusives come with vehicle wise that is missing without them.