It's hard to say. In my opinion, Resident Evil needed a serious change after all those games in the past and Resident Evil 4 was it. Easily one of the best games ever made. You could say it revolutionised third person shooters.
That being said, I believe the series started to go down hill from there. Resident Evil 5 was a good game, I really enjoyed it due to the co-op aspect but it didn't "feel" like a Resident Evil game at all. It felt totally different. Sure, Resident Evil 4 was totally different too but it still "felt" like Resident Evil. 5 however, did not.
Resident Evil 6, what the hell? I was really excited for that game but so, so disappointed by it, regardless of the Leon/Helena campaign that featured zombies. It's lost it's touch.
Is a "reboot" in order, or should they try and continue the story? I don't know how Capcom can help themselves regarding Resident Evil.