I've thought about this recently, and I think I posted about it in another thread. Ideally you'd get a few fans together (I have one or two in mind that might be interested, but haven't approached them) to pool their money and get the IP from IAC. A conservative estimate would be $15k, which is based on a figure someone was given from IAC a year or so ago. I'm not saying $15k would buy the game, but it would get their attention. It's probably not actually worth that much, but it more-so covers the costs of getting everything situated and all the legal leg-work.
Once we have the rights, I'd polish up the current version of Legions to the best of our (and the engine's) abilities. Switch out the textures with the HD ones posted years ago by...PWA(?). Remove much of the engineering code and models to bring down install size and console spam. Fix that damn CTD bug if you're tabbed out and there's a map switch. Fix or just remove Prometheus. Make the map voting process more streamlined. Add some new quality CTF maps and tweak existing ones that have issues, maybe bring back that abortion people called Quarry for the hell of it. Bring back the tutorial from the olden days or just create a new one for new players. The list goes on, but basically just apply a bunch of QOL improvements, and maybe some modern features (in-game VOIP? Bring back stats?)
Once it's in decent shape, slap that baby on Steam. It'd have to be dirt cheap considering its age and being multiplayer-only. Continue to collectively pool your money with the other developers/owners, and use whatever money you get from Steam to start work on Legions 2. This is a pipe dream within a pipe dream, but I'd say it'd be worth doing if you get this far.
Alternatively, see if IAC would be willing to put this polished version of Legions on Steam and let them have their cut. This bypasses the requirement of needing the IP. How Legions 2 would fit in with this...who knows. I'd be interested in joining this little venture, but only if the right people are involved and we've discussed everything at length before bringing money to the table.
I don't think I'd want anyone from Midair involved, but that's just my opinion.