ICEMAN

People have hit the nail on the head when they attribute the lack of success in the Tag-Team division to the Brand Extension. There just aren't enough guys and enough good tag teams for each show.

RAW:
La Resistance
Tajiri & Rhyno
Hurricane & Rosey

Smackdown:
Basham Brothers
London & Kidman
Dudley Boyz

Now, combine the rosters and you've got six tag-teams and a decent tag-team division. With the brand extension, everyone runs out of opponents, leading to a lot of repetitive matches, as well as tag-teams going against two singles stars, just because there is no one fresh left to wrestle.

The tag team division isn't the only thing weak in WWE right now. The main event picture for both brands is thin. The midcards are solid, but there are only 2-4 guys on RAW and Smackdown! that are capable of headlining a PPV right now. Combining the rosters would give us new matchups and make for a stronger card overall.
-Djwlfpack

Tommy 2 Slow

Formerly Narc

I think you guys are right. The brand expansion is whats wrong. With only one show a week to promote each brand, all of the 2 hours are used to put the Heavyweight over. If WWE was one, they would have 4 hours to put everyone over.