The design change was for the best, of course, but even then.. I don't think the movie was all that interesting at all; It's the most generic "CGI character amongst real-life actors" formula ever..
the design change and the delay sure gave them the advantage of a lot of good will of people that before was expecting the movie be a trainwreck; It didn't end becoming one, but had they kept their guts and continued with the old design, I think the movie would earn more critcsm on its narrative too.
I'm a tad more interested on the sequel now that they're actually trying to make more a Sonic story than anything tho; But it's surface level to me, because I never liked the setting of having Sonic in the real world, movie or game. :\
In interviews with the writers they said their first drafts had a story that was much more game-accurate (originally the first movie had Tails and Chaos Emeralds, they said), but studios kept bouncing it back to them because they didn't think it would play well with mainstream audiences. The studios wanted the brand recognition, but not the content. So they forced the "CGI character amongst real-life actors" template on the writers/producers, and they settled for simply sneaking in easter eggs for the fans.
Then the trailer hit.
The backlash didn't only change Sonic's design, btw. People dug around and found concept shots in portfolios of artists who worked on the film that showed a much more realistic home planet for Sonic, and some rando grimdark lizard people were chasing him for his power. During the redesign they changed the planet to reflect Green Hill Zone and changed the lizard people to echidnas, so that first scene would set a
wildly different tone than originally set up. Obviously the generic live-action bits wouldn't be reshot after all this time
but even though the generic story would remain the CGI stuff was all reconsidered to try and make it more Sonicy.
And it
worked. Fans turned up, audiences ate it up, and once Paramount saw that (and the earlier backlash), they had a lot more confidence giving the team more leeway to make a more accurate Sonic movie. So Sonic 2 is sorta the movie the writers/producers were
trying to make in the beginning. And since they were pigeonholed into the "Sonic.. but in the real world!" setting, they seem to be trying to give Sonic 2 some Adventure flavor, as that first bit of the trailer gives off
strong SA1 Station Square into vibes. So they're trying to do "Sonic in the real world" in a way that's a bit more game-accurate, too.
TL;DR: I think the second one is gonna
rock, despite my agreeing that the first one had a generic, boilerplate story.