I'm assuming since Donkey Kong Country Returns is still on shelves for both Wii ($30) and 3DS ($35), consumer perception may have been that $60 would seem unreasonable. Also, I think Nintendo is just trying to do EVERYTHING they can to ensure that Wii U has a successful holiday season both in terms of hardware sales AND software sales so that they can run into 2014 with some momentum. If they can enter 2014 with a higher install base and some sales momentum, Mario Kart 8, Super Smash Bros., and the rest of their 2014 lineup so far will ensure that Wii U is riding high all the way through to the next holiday.
On a personal note, I'm THRILLED that a game I was going to buy either way is $10 cheaper. I have so many Wii U and 3DS games to buy over the next 4 months that every little bit helps. With Wind Waker HD, Wii Party U, Sonic Lost World, and DKCTF all being $50, that saves me $40...which is enough money to buy The Legend of Zelda: A Link Between Worlds or Mario Party: Island Tour!
Upcoming Games To Get
Definite: Kirby Star Allies (Switch), Mario Tennis Aces (Switch), Fire Emblem (Switch), Yoshi (Switch), Pokemon (Switch), Kingdom Hearts 3 (PS4), Monster Hunter World (PS4)
Considering: Fe (Switch), Donkey Kong Country Tropical Freeze (Switch), The World Ends With You (Switch), Ys VIII (Switch), Street Fighter V: Arcade Edition (PS4), Kingdom Hearts 2.8 Remix (PS4), The Last Guardian (PS4), Shadow of the Colossus HD (PS4), Anthem (PS4), Shenmue 3 (PS4), WiLD (PS4)