No way they tear down the amphitheater. Gospel Fest and the Christian Music festival do huge numbers for the park. If they do anything with it maybe they renovate it/expand it but I don't think that's likely.
I too am surprised they didn't do any formal announcement as RRR is a beloved ride. Very sad, but I'm sure we will get something nice.
I personally still think we need more flat rides. I could see them putting a screamin swing (I think it would be a huge hit) or a giant Frisbee like Max Air.
With this and hopefully Dino's Alive leaving soon Carowinds could be set to receive some pretty exciting additions.