Now that I've played some hours I can finally give some feedback on it.
The game itself is fun, at least for the first few hours, I'm not sure about the replay value of it yet because I haven't really sunk a ton of hours into it, but I assume with so many "heroes", and more coming it won't be that huge of a problem.
My main criticism is the movement, holy shit this is some of the worst movement I have ever experienced on an fps or any game for that matter, very clunky movement on pretty much every character, specially on those which should benefit the most from it. Seriously, characters with explosive jumping abilities and no air strafe or maneuverability whatsoever. Very disappointing.
Game is fun, but it's not a "TF2 Killer" by any means, nor it can be because it plays more like a first person moba than an fps. Also I don't see how it can be interesting competitively, from what I've felt from my limited experience, there's a lot of crutches or dumbed down mechanics. It will probably be huge competitively anyway cuz it's blizzard and they can dump bags of money on it.