The way I see it, the WWE Champ feud would go across both shows. So assuming Reigns is champ, he could be cutting a promo on Raw, wrestling on SD, or even have a feud with Cena on Raw and Orton on SD at the same time. The one thing I'd love WWE to bring back is proper number 1 contenders matches (it's the one thing I'd have added to Jericho vs Styles at Mania) so it could be either of the show champs, big names from each show facing each other, anything. Loads of possibilities...
Aside from the belts, I'd also sortbout the writing teams. Instead of having a writing team per show, I'd have s writing team per division - so the tag division has it's own writer, the women have their own writer, the IC title has its own writer and so on. Actually sort out the midcard for once!