If they make Smackdown NXT, they're probably going to lose a lot of network subscriptions. Doesn't seem like the best idea.
It could make way for NXT to truly be devolpmental? IIRC NXT also has some TV deals in place in some markets so who knows what will happen.
I think it says alot that most of the roster (Save for the chosen few) won't know where they will be. And Vince has a history of breaking up teams, family's, crews, and more for not really any defined reason.
I honestly expect Vince to split up every tag team including a team like American Alpha so he can get Jordan away from Gable.
The 3 key points of a brand dependency will be as follows:
1. Vince must have a hands off approach to the booking of smackdown. Let Ward and HHH run the show without constant last minute changes to every script. Idealy Vince should have a list of guidlines for specif things to avoid (Rape, guns, murder, racism based angles for example) but we know that those carny style angles are Vince's favorite.
2. Guys should be designated to a "brand" for a period of at least 6 months or so. If a top guy is injured on the raw or smackdown roster
3. Smackdown needs to stand for something different than raw. When Smackdown was doing better than raw they were pushing the Latino Steve Austin that Vince was never going to push on raw. If Smackdown is able to draw using workrate or something different than typical raw booking it should be awarded and not punished for it. Maybe having new agents would be a help.