I think the idea is that these wing missions can be attempted by anyone, regardless of whether or not they're in a wing. But I do think they should have their own section within station services.
Not a bad idea.
Wing cargo missions are the ideal opportunity to "twink" your 2nd account- do a wing mission on 1st account but dont hand in. Log onto your 2nd account from Steam and share the mission to your 2nd Cmdr. Alt tab across to your 2nd Cmdr to accept and then alt tab back to the first to complete the mission. Hey presto your 2nd Cmdr can now also complete the mission for a freebie payment of Mcr for doing absolutely nothing........
Not sure it works on xbox like that. Might take a look later though.