Fire most of the writers and use 2-3 guys to do the booking. Maybe 2-3 on each show.
Keep HHH around and more or less do what MildlyUpsetGerbil suggests and just tell him to push whoever.
Also organically push whoever the audience gets behind or boos. That means Rusev would get a push, Roman would be a heel.
Also would have a top guy/gal on each show with around 5 or 6 people to feud with.
Any wrestler who gets over organically gets a push. Might not be into the title scene but still.
Use legends to put over up and comers or use them in tag teams or vs other legends. Try not to job them out though.
The champions would wrestle a bit less or at least not be on the shows every week. Make them a bit more of a special attraction. Use the ones around 40 to elevate the up and comers so one like AJ, Samoa Joe, Bobby Roode would probably be in the title scene but probably would not have long reigns.
On RAW Seth would probably be "The Guy" transitioning to Danial Bryan both of which would be used to elevate another 1-2 wrestlers to replace them in a year or two. They are over enough to always be in the top group until they retire.//get injured. Top heel would be Reigns. On SD AJ would be "the guy" with probably Miz as top heel. Would probably put the tag teams on 1 show the women on the other and have some more stables. RAW would be more sports entertainment Smackdown more like NXT. Probably Women on RAW tag teams on SD perhaps switching them each year.
Better booking on both shows though maybe be AE light, tone down the blood, violence etc but have the more compelling storylines for the midcarders.
Intercontinental title would go back 25 years and probably go to the best technical wrestlers some of which could be used to be vaulted into the main title scene.
Have a few top mid carders be positioned to step up in case of retirements, injuries and things like that.
Organic pushes would put wrestlers into the top of the midcard or the top 5-6 guys for the title scene (think Austin with support from Kane/Mankind HHH etc). The IC/US titles would be for the top of the midcard or the top 5-6 main eventers.
Would also use a handful of "free agents" who could drift between both shows as needed. They would probably be some of the older guys (AJ, Cena, Samoa Joe etc) and would be somewhere between part and full time to reduce wear and tear on their bodies. Audiences love them they don't need to be in the ring every week just rotate them so the audience sees someone they like each week though. .