I seem to recall an absolutely, horribly executed Villains after hours event that took place a few years ago. It was so bad Disney offered tons of refunds. They have a formula - it works and most nights sell out. I can’t see them investing more money to revamp this event.
Went to both, both horribly executed, both PROVED that this is a bucket of money they keep leaving on the table. Folks love Disney Villains at an adult level that don't enjoy the Horror at UO. The Unleashed was a good idea but wasn't followed through with any level of good management.
But I think the biggest problem is that I don't want to see the sets, structures and distractions sitting in the parks that UO has. Most Disney guests don't want to see the ambience upended. And I agree with that. Find a way to incorporate it with simple interference with the daytime guests.
They could totally pull off an adult Villains Halloween event at DHS IF IF IF they put someone in charge who knows the park, knows the market and knows how to organize a successful large event in DHS.
NOW if they are talking two different events at MK -
MNSSHP and other nights a Villains/more adult Party ... I would love that. A bit creepier, more villains, more good interactions & meets, no candy, no kid dance parties. Maybe one adult dance party with strobes, smoke and better music. Perhaps a minimal parade like the DRAGON at night with her hard rock music she had during Villains After Hours.
Maybe an awesome castle show like DL has combined as dance party, their Halloween is much better offering. No free food but spend the money on entertainment like Mad T Party and more characters. It could work, I'd buy.