I would have liked to have seen a WCW reunion "One Night Stand" idea about 10 years ago, in about 2004/5. The problem with doing one now is that WCW's top stars were almost all veterans when the promotion ended- Flair, Sting, Nash, Luger etc and are a hell of lot older now, and many are retired/semi-retired. They could still appear as special guests, but most wouldn't be able to compete in the ring.
I think there is just enough talent to make this work, but it would have to be done very soon, rather than waiting any longer.
If WWE were really serious about doing this, here is a list of performers I could see them contacting:
Kevin Nash- still wrestles occasionally on the indies- would probably come back for 1 match
"Hollywood" Hulk Hogan - Back with WWE, could dress in the black/white one more time
Goldberg- WCW's last great star, may not be interested but WWE would love to get him
Sting-We all know the story with Sting, and if he does sign a WWE deal, this could be one of his rare appearances.
Ric Flair- Would almost certainly appear, probably as a manager or as guest host
Chris Jericho- On good terms with WWE and would be open to return.
Rey Mysterio- Still in WWE and could add the "Jr" back to his name for the night
Big Show-Still in WWE and could be renamed "The Giant" again
Booker T- Still contracted to WWE and could get back in the ring for 1 night
Paul Heyman-Still in WWE and could be renamed "Paul E Dangerously" for 1 night
Steve Austin- Contracted on a WWE legends deal
DDP- Contracted to WWE on a legends deal and still makes the odd indie appearance
Sean Waltman-Contracted to WWE on a legends deal and still wrestles on the indies- could be renamed "Syxx" for the night.
Bret "Hitman" Hart-Contracted to WWE on a legends deal, often appears on TV.
Sid Vicious-Appeared in WWE last year- could wrestle a short match
Vader- appeared in WWE last year- still wrestles on the indies.
Scott Steiner- Still active on the indies
William Regal-Still in WWE, could be renamed "Steven Regal" for the night.
Scott Hall-Healthy again and could manage Nash/Waltman
Norman Smiley- Works in WWE developmental- could appear and do the "big wiggle"
Mick Foley- Still contracted to WWE and could be renamed "Cactus Jack" for the night
Bill DeMott-Works in WWE developmental- could be renamed "Hugh Morrus" for the night
Dusty Rhodes-contracted to a WWE legends deal, could manage his son.
Goldust- Still with WWE, could be renamed "Dustin Rhodes" for the night.
Harley Race-Contracted to WWE legends deal- could manage someone.
Stacy Keibler-Rumoured to be open to a one-off return to WWE.
Ron Simmons-Contracted to a WWE legends deal, could manage someone.
Torrie Wilson- Would almost certainly be offered a 1 night return
There are plenty of other wrestlers that could appear who are still active/semi-active:
Juventud Guerrera
Pcicosis
Terry Funk
Lance Storm
La Parka
Stevie Richards
Perry Saturn
Buff Bagwell
Ultimo Dragon
Shane Helms
Vampiro
Raven
Billy Kidman (I think he may still be with WWE in some role)
Shannon Moore
This is the card I would like to see if the PPV happened.
Sting w/ Ric Flair vs Chris Jericho w/Bret Hart
Kevin Nash & Sean Waltman w/Scott Hall & Hollywood Hogan vs The Steiners
Goldberg in a gauntlet match v all of 3-Count, then a final challenger comes out, giving us:
Goldberg vs Diamond Dallas Page
The Giant w/the nWo vs Booker T w/Stevie Ray & Sharmell
Dustin Rhodes & Cody Rhodes w/ Dusty Rhodes vs Rey Mysterio Jr & Chavo Guerrero Jr
Juventud Guerrera vs Pcicosis vs Ultimo Dragon
Lance Storm vs Steven Regal
15 man Battle Royal featuring:
Sid Vicious, Vader, Fit Finlay, Norman Smiley, Raven, Jim Duggan, Crowbar, Saturn, Stevie Richards, Terry Funk, Buff Bagwell, Ron Simmons, Scorpio, Chuck Palumbo, Vampiro, Billy Kidman
A WCW version of Piper's Pit featuring Stunning Steve Austin & Paul E Dangerously
Eric Bischoff would introduce the show and be the "Host"
"Mean" Gene Okerlund and David Penzer would share announcing duties
Tony Schiavone and Paul E Dangerously would be the commentators
"Little Naitch" Charles Robinson and Nick Patrick would referee.
There would be cameo appearances, interviews and skits with Harley Race, Ricky Steamboat, Arn Anderson, Dean Malenko and others.