IMO the main issues are multi-fold and it is almost purely PR related. The game itself looks to be pretty Battlefield and the mechanics seem solid from what I have seen.
1) They understood we live in the "outrage" era, but they also forgot that works both ways: I mean, I really do get why they tried to sell the "we got women in the game!". They were attempting to appeal to a potentially untapped market and hoping to get positive press coverage from main media outlets, but they forgot all the Gamegate shit has 2 sides and people pounced on that. Honestly they shouldn't have led with that as a first impression. 100% they should have kept that stuff in the actual game and even talk about it a bit later on, but they should not have had that be the first impression. BF1 did something similar (you play as a woman for an entire single player campaign) and you didn't hear nearly as much REEEEEing because they didn't use that element to initially sell the game.
2) Battlefield's fanbase tends to be more history oriented: I know this is somewhat hypocritical, since virtually every core BF game has involved prototypes of shit that never actually saw combat or never really worked as it did in the game. However, I would say that part of the draw for the BF games for its fanbase was the historical "accuracy". Ignoring the robo-arm woman, the trailer was filled with so much WTF stuff going on that some people even were speculating if it was some sort of bizarro alt-history WW2. Not a good sell to the history-buff crowd.
3) The trailer's tone was wrong. The trailer didn't seem to know what it wanted to be...was it supposed to be tongue in cheek? A 4th wall breaking representation of a typical online game? After the remarkably well done BF1 trailer, the BF5 trailer just felt off. Yes, war is "chaotic", but there are ways to show representations of that without it being "chaos" if that makes sense. Without showing a single gameplay element, it felt like a BF game straying from its roots and unsure of what it wanted to be. This is part of the reason why the CoD in Space game got shit on by the gaming public. Granted, if they revealed the title "Bad Company 3", people may have cut it some slack because that offshoot was never the "grim dark" serious games that the core BF games are (although Bad Company 2 was fucking amazing gameplay wise in multiplayer).
