I don't know why Activision plays these waiting games with Nintendo fans. It makes no sense even though it's not like the Wii U version is going to sell a million or even half a million copies (at least not likely given the low install base and flood of upcoming 1st party titles). Activision did this stunt with Black Ops 2 by announcing it in May of last year, but not confirming the Wii U version until September. I feel sorry for the few fans that want it on Nintendo's platform, but are left waiting on Activision to give them the thumbs up or not already.
It's so (in their mind) they have an excuse as to why the game didn't sell.
Stupid, I know.