I believe Manchester-Las Vegas was last served in April/May 2020 by VS.
I could see a return to Las Vegas, but I think Los Angeles would also be a really good route for them from Manchester. Capture some of that traffic currently connecting with BA at Heathrow and through other European hubs.
I think if they are stumped for growth at Heathrow and aren’t returning to Gatwick, Manchester should see some decent route growth and development.