Unifying the World Titles
I wouldn't do this for the simple fact that having two world titles makes it easier for mid carders to get that push to the main event level, even if having two world titles lowers the value of each of them it is worth it to start seeing more of our favorite mid carders like Kofi Kingston, John Morrison, Dolph Ziggler, etc.
Tag Teams
Either get more tag teams or eliminate the titles. Two guys there are doing nothing right now that could team up are Sheamus and McIntyre, like you said you could bring back older teams like Benjamin and Haas, I believe they are trying to do this to a lesser effect by reuniting Ryder and Hawkins.
US and IC Titles
For the US Title put some one like Swagger against Kofi for the title, Evan Bourne could use the title too, it just seems that Kofi is the keeper of the mid card title of whichever show he is on till they have any ideas for it, so get it off of Kofi, help him out with his mic skills or give him a manager and give him the big push to the top. For the IC title I would give it to Jackson like I think they are going to do, besides they need Barrett to start performing like he did when he was with the Nexus because SmackDown doesn't have a lot of top tier heels right now.
PPVs
I would say once a month right now, eliminate some unneeded PPVs like Hell in a Cell and Over the Limit, once they are faded out start having 8 or 10 a year, making it a bigger deal when a PPV roles around.
Stories and Promos
You have to stop righting everyones stuff for them and let them have a little freedom, that is the only way some mid carders can get over, I believe this is the reason why John Morrison's promos tend to be boring like he is reading it from a piece of paper, its because he basically is.
Crusierweight Title
Heck yeah bring it back, have guys like Sin Cara, Evan Bourne, and Tyson Kidd fight for this title, they could put on some great matches, As for who to put it on at first, put it on Rey Mysterio, and I say Rey because if you give him a 3 or 4 month title reign with it then drop it off to a mid carder like one of the guys above, it will get them over with the crowed, especially a heel like Kidd.