When it comes to crowning a new world champion in WWE, it's important to boost the new guy's stock as much as possible from the outset. This can be difficult when you're moving the title between two of the company's most popular figures. You can't have the next top babyface beating out the previous top babyface, because it will divide the fans and suck away a lot of the momentum.
Enter the transitional champion.
These guys aren't meant to be the focal point of the company. They're simply an intermediary between two "true" champions, - both of whom are usually babyfaces - used as a buffer to make sure neither of the full-time champs' reputations are hurt.
There are three key elements necessary to qualify as a transitional champion: 1) You're winning the belt in order to drop it to a different guy later on, 2) The guy you're taking the belt had a substantial and lengthy reign, and 3) Your reign isn't meant to be substantial or lengthy.
Now, given that somewhat woeful description of what constitutes a transitional champion, you might think that this list is going to be nothing more than a Who's Who of crappy titleholders. But just because a guy wasn't necessarily meant to be a memorable champion, that doesn't mean he can't be one.