As part of the development team, I'd very much like to see some evidence too.Couldn't quite find anything in the Giant Bomb thread (didn't browse it all).
Trine 2: Director's Cut should be using slightly higher graphics settings on Wii U than Trine 2 on the other consoles - nothing really major but a tiny bit. Also the new Goblin Menace expansion levels simply wouldn't run on the other consoles right now, they're more demanding than the normal campaign levels and we've done a lot of optimizations on Wii U to make them run well. The only possibility I can think of for "effects missing" is that if we've had to optimize the Goblin Menace levels we've accidentally disabled some effects for the main campaign too. But let's see some real evidence first and I can provide the tech answer (or semi-tech, I'm no programmer myself). If some effects are truly missing, we'll fix it in an update.
Also I have to apologize to North American gamers - we actually wanted to have a small discount at launch but sadly that wasn't possible just yet. We're going to have it in Europe but of course that's no consolation to NA gamers. Sorry!
Anyhow I hope those who buy the game enjoy it very much!
Best,
Joel
Frozenbyte
These dudes seem to think it's mostly related to the lighting.
http://www.neogaf.com/forum/showpost.php?p=44493294&postcount=9465
http://www.neogaf.com/forum/showpost.php?p=44493286&postcount=9464
http://www.neogaf.com/forum/showpost.php?p=44493257&postcount=9462
http://www.neogaf.com/forum/showpost.php?p=44493274&postcount=650
I only own the PC version so I can't say for certain.