#8 Raven
For a while, Raven was one of the most compelling and mysterious characters in professional wrestling. He had a unique look, his promos were brooding and articulate, and he had enjoyed success in just about every promotion he landed in.
So what did the WWF do when they signed him? Simple? Well, they changed pretty much everything about him.
Debuting at 2000's Unforgiven PPV, Raven helped bring a merciful end to the lacklustre Tazz/Jerry Lawler feud by planting Lawler with a DDT. From there, he entered the Hardcore division, winning the titular Hardcore Championship a record 27 times. Sure, this seems impressive, but bear in mind that the Hardcore Championship was basically just a glorified game of "Hot Potato".
His longest run with the title (which was also his first run with the title) was 31 days long. Additionally, he only held the title for a combined 84 days, meaning that his reigns lasted 3 days each, on average. Also, many of his title victories weren't even televised and lasted for less than one night. Sure, the "24/7 Rule" was entertaining and the hardcore matches were fun, but his record-breaking title count is a lot less impressive when you put it into context.
Anyway, while all of this was going on, Raven got very little promo time. This was one of their biggest mistakes, as Raven was lauded for his mic work. He also ditched his signature curled hair, leather jacket, t-shirt, and jorts combo in favour of dreadlocks, no shirt, and a kilt. When he finally started getting more promo time, it was on Sunday Night Heat, WWE's C-show. Insert cliché about a "tree falling in the forest" here. Finally, in January of 2003, Raven was released from his contract, having won very few matches prior to his exit.
I'm not saying that Raven definitely deserved to be a World Champion in WWE, especially with industry giants like Austin, Rock, and Undertaker running the show at the time. What I am saying, however, is that Raven could have been a solid mid-carder, at the very least. Instead, WWE barely used him.