15 years ago? Nah not at all. You really need to watch mind games with HBK vs Mankind which is one of his greatest matches that wasn't even a gimmick match. Was way quicker in the ring then as opposed to now. He was better in the ring than he was given credit for back then.
I have watched that match and it was great but besides that match, back in the late 90's, early 2000's he was about the same shape as he is now. It's just how much he works I guess. I mean he has been up and down throughout his career.