I'm not even going to entertain neigh-saying comments before we even have a trailer, let alone legitimate confirmation of the movie. Just because bad movies have existed before doesn't automatically mean that a Sonic movie will be one of them.
I heard about this just the day before, and I am excited!

I've wanted a Sonic live action/CGI mix movie since at least Sonic Adventure 2. And no, I'm not counting that crappy fanfilm by Blue Core Studios. I want to see Sonic and friends with character models closer to what we've seen in the games. I definitely want to see them use Modern Sonic, since many of his games played out like movies anyway. And I don't care if it's a darker, edgier film for long term fans. How dark could it be? It's Sonic, for crying out loud! Worst we might get is something similar to the Sonic '06 story. Yes, I mentioned the game that must not be named, but it only sucked because of load times and bad game mechanics. The story it had is much more enjoyable, despite a certain kiss scene, and it wasn't any better or worse than the stories we had seen in the 3D Sonic games that came before it.
But even if the movie turns out to be crap, I feel like we should support it anyway. At least enough to show that a Sonic movie could definitely be successful if done right. And the way to do it right is through 2 simple steps. The first is to always have a constant dialogue with Sega and the Sonic Team, make sure they have a bible of do's and don'ts, and make sure the movie reflects the version of Sonic most people have come to know through games and the more recent cartoons. The second step is to find some solid writers that would honor the lore of the main Sonic canon, and considering the writing in the recent games (and hopefully Sonic Boom) has been so good, how hard can it be? The worst thing they could do is give someone complete creative control without any context or understanding of the Sonic franchise. If that happens, we could end up seeing something just as weird as a movie based on the Archie universe.

(No offense to Archie fans, I just don't think that's what's best for Sonic right now.)