As expected, any change creates strong emotional reactions.
My 2 cents - this type of change is exactly what every attraction should go through the scrutinty of. I love the original Country Bears Jamboree; but, I'm not going to sit and pretend that it was pulling it's weight in a park that still is in dire need of capacity.
Of course, I could insert the ad naseum Walt axiom about the parks not being a museum; but, in this case - there was a piece of prime real estate in the park that could either undergo a wholesale makeover into something completely different or even worse - get shuttered like so many other things around the resort when they can't pull their own.
What I immediately picked up on with this makeover versus other attempts on different attractions is that the tone and framework of all the show beats that worked in the classic version are still present even if what was being sung or said has changed. It still 100% feels like the Country Bears. It's just they are now singing a different tune. In this case, change is good.
In the long run, this is exactly what should happen with every under performing attraction as history has already shown us that true addition to the parks (by actually adding new things without taking away) is very, very infrequent. Simply, TDO is adverse to spending more on labor and maintenance and would rather steer crowds around the parks to what is already present (with the exception of what lies beyond Big Thunder and in Adventureland as they've finally given up on trying to keep people out of MK and instead just want to cram more in).
Thinking this makeover through and applying the lessons learned here to other updates think of the Imagination attempts. They have failed because they were changes for the sake of changes. The quality and tone couldn't match or exceed what was there before even when they attempted to make the second attempt closer with the addition of Figment - the tone of the attraction and character were still different.
Hopefully, this version of Bears will be a success and steer some crowds its direction and when it stops doing that - simply revisit it again. The Bears weren't broken... they just needed a new coat of fur and tunes to bring people back.
In short... don't throw the Bear out with the bathwater. Simply lather, rinse, and repeat.