The obvious answers are McMahon, Russo, & Arquette, because they aren't wrestlers.
But when I think of wrestlers that shouldn't have gotten it...
Sheamus = A friend of mine made the comment that Sheamus winning the title would be like if WCW put the belt on Mike Sanders, and he wasn't far off. Nothing against him as a talent, but he was so underdeveloped that he didn't belong in the title picture. He literally went from Jamie Noble to John Cena overnight.
Great Khali = The only justification for putting the belt on Khali is that he's so big that people would view him as unbeatable. Here's the problem though. Right before he won the title, Cena pretty much kicked his ass twice, including a tap out victory and giving him the FU, so the monster image was pretty much killed. And unlike Big Show, he's not talented enough to make up for having the monster image ruined.
Diesel = I actually like Nash as a talent, but he won the title and was not ready for that push, let alone a year long reign. He didn't have enough build up, promotion, & wasn't put up against very good talents in alot of his main events (Sid & Mabel...wow).
There were other guys that won the title really soon like Yoko, Angle, Lesnar, & JBL, and I wasn't sure about them, but they ended up doing well, so I won't list them.
@ op: jbls title reign was very solid, happened in a low period for the wwe but he played his part to perfection. shaemus is easily the most undeserving champion.
2 years ago you sheep would be saying Cena, Batista and Rey.
People are still saying Rey. It could be 10 years from now, and I'd still say Sheamus' 1st title reign sucked because he wasn't ready for it and he wasn't over.
You're supposed to be over before you win the World Title, not months after.