Ah sorry guys, didn't notice the new replies.
Hmm. You mean the Wii U GamePad screen looks worse to you than the TV? For most people it's the other way around, the GamePad has fantastic output... I'm not sure on the tech side, I don't think we at least do anything special, we should be just mirroring it.
However in the case of Trine 2, we'll have the update out very soon (this week I hope) and that will change the colors drastically, affecting both. (Basically it fixes the washed out gamma output, which hasn't seem to have bothered that many players after all, but should in any case look better to most eyes.)
As suggested above I might look into the TV settings and see if it's using any special modes to boost colors or something (for example 'Dynamic' could look more colorful than THX/Standard etc). That's the only thing I can think of, the GamePad should be able to produce pretty good colors... But yeah your explanation of wireless compression would also make sense. We have no real info on that, sorry.
Yeah we use "Frozenbyte" to interact on Miiverse. I have JoelFB but it's on the same console so not used much.
Thanks guys.