I feel Danielson's case is mainly performance based. And yes, those of us that rate him highly will always sing his praises and argue for him to be placed on a "greatest ever" tier. But to me, historical importance goes beyond that. I don't think the business changed or flipped when he was active and it certainly didn't suffer while he was/is gone. His WWE run is the one thing you could make a case but I feel like without Punk, Bryan might not even get signed in 2009 and by Dragon's own take on the matter, without Punk leaving, he wasn't maineventing WM 30 either. And his injuries didn't let him have a proper run on top to make a case of any lasting influence either. The one big lesson Vince got from Danielson was that he could book babyfaces like complete losers and maybe the people would get so mad at him that they would rally behind and get him more over (which didn't really work with anyone because Dragon's case was unique).
Him being part of indy wave of the 2000s is relevant, for sure. But again, I feel other wrestlers were more important than him in making it as special/important as it was.