I don't buy this. The studios will make changes regardless if we protest on Hollywood Blvd, put a petition on Change.org or threaten to kill a bunch of puppies. Change is going to happen to these properties even in the comics...there was a time when bringing Bucky back was high comic book treason.
Maybe... But I think that with this comic book movie renaissance going on right now, the makers of these live action superhero products are going to be trying a bit harder to please the fans. The fan community is bigger now than it ever has been, and with things like twitter, our voices can be heard more easily. Amell and the writers are pretty in touch with the fan community. I'm sure if there was a big enough fan outcry towards some aspect of the series, that they would seriously consider our opinions.
And since we're talking about The Flash, which is a spin off of Arrow, I'd say that the situation with Arrow is pretty similar to the way it is with The Flash. Basically what I'm saying is that if enough fans complain about something to do with The Flash show, I wouldn't be surprised if the creators rectify things to get in good with the fans.
Right now, there's not too many people hyped about The Flash show. The Flash isn't a huge beloved comic book character, despite how long he's been around. A second season of this show isn't even a sure thing. It's spun off from a successful show, which helps, but The Flash has already failed on television before, and his recognition factor has only changed slightly since that last series.
A first season is a pretty delicate thing. They're going to try their best to keep us happy, and being critical of the negative aspects of the show could possibly yield a change on the show. I'm sure at least one person working on Arrow is at least a little bit interested in what the die hard fans of the character think about the show. And the SHH is one of the best places to find said die hard fans. Apparently (someone back me up on this, I've definitely read this before, but don't remember who said this, I believe this information came from a mod) in the past, filmmakers working on superhero movies have been known to peruse the boards from time to time.
Right now I feel comic book fans are overly critical...we complain of every little thing that isn't ripped right from the pages...and then when it does we complain that every little thing was ripped from the pages.
Sure yeah there are people like the ones you're talking about, but the vast majority of comic book fans (at least around here anyways) are pretty level headed and logical when it comes to that. Sure there are trolls here and there that do what you're talking about, but for the most part, comic book fans around here don't really seem like that to me. Most of the time, the complaints aren't without good reason. The trolls only come out to comment the day of whatever announcement they perceive as negative. The fans that stick around to talk about it are typically a lot more reasonable.