The only way to do a successful brand split is to bring back WCW. Turn Smackdown into WCW Smackdown and give it an entirely new look and feel reminiscent of southern wrestling.
Bring Shane McMahon back for a one time appearance to play off of the 2001 angle that he bought WCW out from under his father and now has been buying up WWE stocks and plans to take that money to buy out Smackdown's time slot and re-open World Championship Wrestling.
The World titles will have to be separated again with the Big Gold Belt going to WCW along with the US title. In addition the WCW World Tag Team and Cruiserweight titles will be reinstated and brought to WCW.
It will also be especially important to keep the feel of both shows different so that fans feel like they have a choice as to which style and roster they prefer. WWE RAW can remain the cartoony non wrestling program that Vince likes while WCW Smackdown! focusses on the sport of wrestling.
Since PPVs are becoming afterthoughts anyway since many fans get to watch them on the network, Vince should go back to focussing primarily on the Big 4 Royal Rumble, WrestleMania, SummerSlam and Survivor Series. These PPVs will feature both promotions with Survivor Series taking on a whole new meaning. It will return to it's original format of all elimination matches, each one featuring WWE vs WCW. It will something for fans of both brands to look forward to as it becomes kind of the new bragging rights PPV, but with a classic feel.
The other PPVs will feature either just WWE or WCW (hopefully Vince still owns the trademarks to "Starrcade" and "The Great American Bash)