NXT involved in a draft just won't work. The whole concept of NXT revolves around building future stars and veterans who have never been in WWE like Samoa Joe, Finn Balor, Hideo, Owens, etc.
I do think a Raw and Smackdown draft can work. Maybe not at the moment, but in the near future. Bring back the world title, women's title, and world tag team titles (the belts from the late 80's till 2001 were the best design). The current roster has a very stacked mid card and a lot of guys not anything big like Ziggler, Rusev, Barrett, Swagger, even Fandango can play a bigger role lol. A lot of top guys like Ambrose weren't even on the last PPV.
They have enough talent to fill two tag team and diva's divisions. What are the Primetime Players and Lucha Dragons doing besides jobbing. Both teams can carry gold. Sheamus and Barrett are teaming, the Usos are coming back, Rowan and Harper are together again, Los Matodores are getting new characters (again). Rhyno and Corbin can either team again or chase the IC or US titles when they get called up. So many possibilities to give pushes and build talent with two rosters. As far as women, Becky, Sasha, and Natalya are currently lost in the mix. I know they're not losing popularity any time soon, but they're ready to be featured, instead they are taking a backseat to Charlotte, Paige, and Nikki. What happens when Baylee and Asuka get called up? Two rosters will help give more opportunities for these performers to shine.
As far as main-eventers, longer and drawn out feuds can help until midcard guys are ready. I'm sure guys like Owens, Cesaro, Ziggler, Rusev can all challenge for a world title if given the push and direction character wise. Imagine Champion Rollins vs. Ziggler feud on Smackdown for the big gold belt next year or Wyatt vs Balor (Demon version) for the WWE title on Raw. Samoa Joe can easily challenge for a world title when he joins the main roster. Even Bubba Ray proved he can carry a main event feud.
There may have to be a throwaway match on Raw featuring Smackdown stars as filler considering Raw will still have 3 hours. With the network, they can have 3 Raw and 3 Smackdown PPVs. 6 big PPVs: Rumble, WM, Money in the Bank, Summer Slam, Survivor series, and maybe a returning King of the Ring with a tournament featuring both rosters and a finals match between a Raw and Smackdown superstar. Have it at the end of the year.
But this is all fantasy talk. Having two rosters or not, it's creative and Vince that really have to get the ball rolling. They have the resources, roster size, and people waiting for an opportunity. There's just too much complacency and just plain last writing and story telling these days. So much talent with little to do.