Gangrel - I know he was supposed to have a return as the stablemate of Kevin Thorn and Ariel, but sadly that never happened. If he was able to work the 'weight issues' out then I think he'd be great to return. He had a great entrance, great theme, great gimmick. He was great overall. I remember being terrified of him when I was younger, he worked the fear gimmick quite well. Not to mention it may be intelligent for WWE to take advantage of the recent 'vampire craze' in media.
Head Cheese - I know we're talking about tag teams and this may seem like a way out of left field pick, but the contrast in the characters of Snow and Blackman was comical, not to mention it could be a way to bring back the hardcore division (which was mentioned on WWE.COM about a month ago if I remember correctly).
MNM - I thought MNM was always antertaining, and such natural heels. A few of you have mentioned bringing back JoMo with Miz, but considering Miz's 'take out the trash' storyline not too long ago, it wouldn't make sense. But MNM would be a great way to bring back JoMo and still help the tag division.
Hurricane - Hurricane (not Gregory Helms, as good as that run was) was so over. Think of how he over he could get with the kids. Of course he would need to use the Hurri-slam...otherwise it wouldn't be the same.
Lita - Lita is one of the more interesting, and talented Divas in the past decade. She had a look, attitude, and moveset that made her vastly different from the rest of the Divas. I think she would be a good asset in an attempt to turn the Diva's division around.
Trish Stratus - Honestly this pick is obvious. Trish Stratus is probably one of if not the most over Diva from the last 10 years. She is great in the ring, fantastic on the mic, all around a great wrestler. Like Lita she would be valuable to turning around the Diva's Division.
Candice Michelle - Candice was a great face and she really improved over her WWE tenure. She, like Trish, was over with the fans.
Raven - Great in ring psychologist, great gimmick and like I said with Head Cheese he could help WWE reach out to fans of hardcore wrestling.
MVP - I think he was a great heel, and while he was worth watching as a face he really shined as a villain. The VIP Lounge was always entertaining, his promos were great. He was just a guy I loved to hate.