Why are there (still?) 6 slots in the mission menu? "Still" is refering to old player made missions, as these might have been inteded for the 3 never used slots.
Well here is an idea, make all quests, Ash, Proffesion Quest, Dodga etc, take the 3 lower slots, so that we can still have 3 normal missions. Quests taking up normal mission slots can be very annoying in teammissions. IE the Dog Tag quests kinda requires you to have the quest WHILE doing missions, etc.. I know you can work around this by just deleting the quest and get it again later, but thats kinda a stupid workaround, dont fit in a RPing way....