You don't have to keep the original 50, at least that is how I heard the voting was going. That said, I would just look at players since the original 50 and see how many I come up with that are clear cut. Then start narrowing it down the players like Dominque that were left off last time and compare them to what we have left.
Obvious clear cut additions
14 - Lebron, TD, Kobe, Dirk, Garnett, Durant, Wade, Iverson, Giannis, Curry, Leonard, Kidd, Payton, Anthony
Pretty obvious additions
8 - Paul, Allen, Pierce, Harden, Westbrook, Nash, Howard, Pau
Then you have the rest of the newer guys you could at least make cases for already:
Butler, Manu, Parker, B. Wallace, Webber, Carter, McGrady, Ming, Mourning, Davis, Dikembe, Lillard, Bosh, M. Gasol, Blake, Aldridge, Amar'e
Then you have the guys that are rising fast or could still do more:
Jokic, Embiid, Doncic, Irving, George
And of course guys like Rodman, Nique, McAdoo, and Reggie that didn't make the cut.
The real question for me is do you take people like Pete Maravich, Paul Arizin, Lenny Wilkens or Robert Parish off the list
I guess I'd have the original 50 minus Lenny Wilkens, Pete Maravich, and Paul Arizin, plus the 22 from the first two categories and Vince, Nique, Mourning, Bosh, M. Gasol, Rodman