Prediction: Splatoon – 1 Million Worldwide by end of May 2015

[mine]

Platina said:
No... it won't sell at a MK8 level :/

It will be as good - but the sales curve will be different. 

MK8 was very steep at the beginning. Splatoon needs more time.

At the end both will have almost the similar attach rate as the power of mouth to mouth will work for Splatoon.