Here is my thoughts. First, I can't say if the film itself will be good or bad. Did I like the trailer? Nope. Why? Because for one, it seemed to reveal too much of the plot. That trailer could of been broken down into 3 smaller trailers, and probably would not of gotten as much heat on the film.
Second though, he's not wrong, there most definitely does appear to be a campaign to downvote. Look at the comments section of the video. People saying they came in, paused and only downvoted. Feig's response though wasn't the right way to handle it. If he truly wanted to shut the trolls down, he could of simply disabled voting and comments, and bam, the trolls would have no where else to go.
But my final thoughts, The assholes he spoke of, they make themselves look petty and childish. But his calling them out, has not helped his image either.