I would love missions to come back, but if it's dependent on Invictus it might take a while; and maybe they want money. Frankly, they should be happy someone is actively working on a game which, in truth, although I like it, is really rather outdated - that said, it's quite popular now to resurrect games and some of them are still just as playable as they were 10 years ago. A lot of recent game "development" has involved super-shiny graphics and no or little new actual gameplay; and the super-shiny brings with it massive requirements for computing and graphics power. I don't see frame-rate issues on PT ?.
Long may PT continue, and I hope enough people join in to make it viable long term.