why cant you have more then one mission and have other people make missions so lets say you wonted to make a mission you would have to put the money in explian what the mission was so when some one did the mission with you the get the money right away and there was no way to get ripped off and for the exp they can split the exp or depends on how hard the mission is just get the same amont of experience

Player made missions have been suggested before. They might be in the development plans.

About multiple missions. I personally like the current system. It forces the player to consider whether they take a missions or not.