New Jack in ECW. Not that his style didnt fit, but his stuff always seemed to be in its own separate universe away from the main ECW brand, he didnt even really get involved in any of the major angles (that may or may not be a bad thing, depending on how you feel about him).

New Jack mixed into the ME sometimes. The Dreamer/Dudleys feud of '98 saw New Jack mix in, Rhino's run with the TV title was a major program and the match with Jack was presented as a big deal...yeah, he was never World title material, but neither was half the roster.

As stated before, Mr. Perfect in WWF in 2003. Also, Dean Malenko's entire WWF run was odd.

 

I actually really liked Matt Bourne's short lived run in ECW as Doink, but I love that gimmick.

Johnny B. Badd was a weird one because that gimmick always seemed like a WWF type gimmick which somehow worked in WCW. Then he went to the WWF without the gimmick and was worthless without it.

 

Bam Bam Bigelow seemed out of place in late 80s/early 90s WCW. But fit in fine in the Nitro era.

 

As mentioned Dick Slater was a terrible fit for the WWF with the gimmick he had. I never realised he'd even had a run there until Sky started showing old WWF shows in the early 2000s and he popped up. He never appeared on a PPV, never had an action figure, or even appeared on something like "if you only knew" music video which seemingly had the whole roster lined up to sing divided into heels and babyfaces. On a related note, the only way I realised that Dan Spivey had an 80s heel run in WWF was because he was in that, in the heel group.

 

Maxx Payne/Man Mountain Rock never fit in the WWF. They gave him that stupid WWF logo guitar which was totally not his gimmick.

 

Shane Douglas never fit in the WWF, either run.

 

Goldberg in WWE.

 

Steiners, or Scott Steiners solo run,

 

Lawler seemed really out of place in the WWF when he showed up late in 1992. I never would have believed in a million years that he'd still be there almost a quarter of a decade later.