I smell something rotten...
The hype machine has been on for a while, the game has been in development for a while and we are expected to believe a veteran triple A company the size and scope of Activision/Blizzard will develop a title first with no plans or ideas on how it will monetise it...
... yeah right, how daft do these guys think we are.
My guess is that they want to see how it launches initially, if the uptake is strong and it gets a good foothold in the eSports arena (which it is aiming at) it will microtransaction the crap out of it, probably come out with some PR rubbish claiming fans demanded the game go F2P and ActiBliz always listens to their fan wallets... I mean voices, yeah voices.
There is a precedence for my claims too, dont forget TF 2 was a pay to play game at launch and ActiBliz execs may think Valve got away with it...