I should point out I don't think Shane was a bad wrestler or bad promo guy for a while. He really did have the juice in 1994-1995 in ECW and is entirely believable as what he said he was...in the context of what ECW was. He was good in his second WCW run (the Steamboat tag run). He did nothing of note in the ring as Dean Douglas to really judge, and his character did not lend itself to his particular promo style. He had three main problems after a while:
1. His body completely broke down when he should have been in his physical wrestler prime (early to mid 30s)
2. He developed a promo style that would never fly in WCW or WWF, so he was instantly going to feel neutered by default
3. He tied himself to Ric Flair, meaning he was always going to get compared to Ric Flair. Shane Douglas isn't Ric Flair.
He was already a husk by the time he left ECW, so when he got to WCW again he was completely broken down, couldn't go 3 months without getting hurt, was neutered by default promo wise, and had very little to offer. Anything after that point is obviously going to get even worse, but that he's still doing this in 2018 when he bumps about as much as the Honky Tonk Man and has been wrestling in oversized t-shirts since 2004 in no name local indies while the guy he raged about his whole career has cheated death, become a crossover celebrity, and is honored damn near weekly on TV is pretty pathetic.