I'm obviously not a game developer. But from my observation the main reason so many people are hating on ND is truly not the leak itself. ND already had a target on its back for two reasons:
- Druckmann being quite open and direct in interviews about the political and progressive aims of his stories, and saying other things that overall will necessarily catch the attention of people who disagree and want to proudly voice their disagreement even though they were never going to buy the game anyway to begin with (also, personally I think it is immensely stupid that he said "we don't use the word 'fun' ")
- The rumors about crunch
Regardless of the validity or lack thereof of these things, it caught the attention of lots of people who feel the need to act morally superior to a game company they see as being compromised and not interested in the quality of their games, even though those people were never going to buy TLOU2 to begin with anyway. (but because of the crunch rumors, even some people who were fine with ND found something to be negative toward)
So, when contents leaked, those people who were waiting for ND to shoot themselves in the foot and prove their point decided to interpret the leaks as proof the game suffered from whatever moral decline is expected of ND (even to the point of actively sharing false information about the contents of the leak).
Personally I think this whole thing is stupid. Most people I see complaining about the game and "cancelling" it were hardly interested in buying it to begin with. And one hour and a half worth of leaks isn't going to show the most important part of the storytelling, which is the actual execution and pacing and how it is tied to the gameplay experience.
Assuming the rumors about bad workplace environment are not true, there is really little ND could have done to avoid this backlash, except not mess up and get themselves hacked obviously. At best, maybe Druckmann could say some less bombastic things, but as the director and writer he gets to say what he wants, and I think the actual games have far more nuance and depth that his words in interviews would let one think. Also... as I said the people who perceive the game as being nothing but "SJW propaganda" were never going to buy it to begin with, because what they actually want is to pick a fight and complain that a successful game developer has a different perspective than them.
TL;DR There is practically nothing that ND could have done to prevent the backlash, and much of the backlash is unjustified and stirred up by people who were not going to buy the game anyway. Really, the main reason the leaks are interpreted in the worst way possible is because of the already negative image ND has along some people because of "controversial" things Druckmann said, and because of rumors about workplace problems. But even if ND fixes their image in some manner it won't change anything for the people who have already chosen to see ND as embodying whatever particular issues they see in the game industry. At this point all they can really do is just release their game when it's ready and pray that game journalists don't jump on the anti-ND wave for clicks. I expect TLOU2 to be a masterpiece so hopefully the hate against the game dies down when people actually play it.