To keep it as concise as possible: not enough content. Too few maps, nerfed vehicles (the tanks have an unrealistically low ammunition capacity that basically makes them useless).
Not the sort of dynamic “battlefield” us BF players are used to.
Pretty boring game honestly, and this is from a long time BF fan.
Update: overall the game has improved. Still too few maps, and the TTK is stupid, but its come a long way and if the final release of content (6 months from now?) provides enough additional maps and maybe fixes some of the TTK issues then this game will have finally earned its place as a respectable BF game. As it stands it is actually a lot of fun to play (especially Pacific Theater maps) and a lot of balance changes including larger maps have made vehicles a more prominent feature in this game.
Vehicles are battlefield, without them u have just any old shooter