I've stated my case for why I like the emphasis on tag wrestling before...but, just to reiterate...
Old school mentality...putting guys that aren't ready to be singles stars into tag teams help them get better faster...nothing gets you more prepared then doing it for real...waiting forever for guys to be singles stars gives you mid-00's WWE...it sucks.
Tag team wrestling, is usually, very low stakes wrestling. The 50/50 booking works better in the tag scene then it does in the singles scene.
Because it works well with 50/50 booking and its low stakes, you can load up a RAW or Smackdown with tag matches and have good, long form, entertaining matches where the result isn't as important. This ends up putting more emphasis on singles matches...singles matches should be special...you should pay, or tune into final segments to see big singles matches.