What I'd like for the shakeup:
To Smackdown (from Raw): Ambrose, Balor, Rollins, Miz, Cass, The Club, The Revival, James or Bliss
To Raw (from Smackdown): Styles, Corbin, Ziggler, Kanellis (both), Orton, Dillinger, Fashion Police, Benjamin & Gable (maybe, see below), Becky, Carmella
To Smackdown (from NXT): Andrade Cien Almas & Zelina Vega
To Raw (from NXT): Authors of Pain, No Way Jose
I also want Sasha going to Smackdown and Becky to Raw, but Sasha/Bayley is going to happen and Smackdown is already getting Asuka.
The way I see it:
Styles moving from Smackdown will be a big loss, so sending Rollins along with Balor and Ambrose will keep the brand afloat and draw good audiences for their live events along with Nakamura as Bryan isn't likely to work those.
Roman and Styles will keep the Raw brand afloat headlining (or co-headlining) the live events along with Strowman, Joe, Cesaro, Sheamus, Wyatt, The Hardyz and Orton for the male roster.
Smackdown gets a big boost to their upper mid-card picture adding Miz and Almas, while Cass can be the "big guy" of the brand. Miz can also resume a possible Bryan program, and it's a "safe" program for Bryan to work as he slowly gets back into in-ring competition as a singles competitor.
Raw fills out their cards (for TV and live events) with Corbin, Ziggler, Dillinger and Kanellis when he comes back. Raw also loses two tag teams (one being The Club for obvious reasons to Smackdown with Balor), but gets a fresh one in The Fashion Police to eat TV time with their backstage segments instead of being relegated to WWE.com segments, but most importantly, they add a new, monster tag team in The Authors of Pain (I didn't send The Bludgeon Brothers to Raw for this reason). AOP vs. Sheamus/Cesaro would be sick. Raw really does need a better, more legit tag division though, so you can even make the case for sending Benjamin and Gable to Raw now that they're lost in the shuffle on Smackdown again. You can't send The New Day or Usos away imo.
Bliss or Mickie is just to fluff up the SD women's roster. That division belongs to Asuka and Charlotte for the year, but I did want to send Sasha to Smackdown so she can have a program with Asuka. Becky needs a reset and is just lost on Smackdown, being shuffled behind Charlotte, Natalya and now Asuka coming in.
So, hypothetically, if things did play out like this, your top talent (and superstars to help bolster live event cards for) for each brand end up being:
Raw: Reigns, Styles, Rousey (TV-only, maybe live events? I don't know her contract), Strowman, Joe, Orton, Elias, Wyatt, J. Hardy, Sasha, Cesaro/Sheamus, WOKEN Matt, Authors of Pain, Becky, Corbin, Bayley
Smackdown: Bryan (TV-only, for now...), Rollins, Nakamura, Balor, New Day, Ambrose, Owens, Zayn, Usos, Asuka, Almas, Charlotte, Miz, Bludgeon Brothers, Rusev, Roode
Obviously it won't happen like this because WWE really doesn't seem to like giving Smackdown a fighting chance when it comes to these splits, but I hope it ended up something like this. I think it's a perfect medium where Smackdown has the roster to pull in good live event numbers and have a quality show weekly and can be "the wrestling show" whereas Raw is the good mix of wrestling and characters, and has enough talent to still fill three hours and have a really good live event card.
I don't want to see just a small shake-up though. I'd like to see a decent number of superstars moving around.
Another thought just randomly, I'm not against sending KO and Zayn to Raw (or one of them) and sending Joe to Smackdown, but the only one of those guys in there Joe hasn't worked with since entering the company is Ambrose and Bryan of the top talent on the would-be SD brand.