My gripe is starting a premade party to run a dungeon and not being able to add someone later on. I've had several instances where we're halfway through a dungeon and someone has to leave. You cannot add someone from duty finder or another friend or FC member to the party to help finish out the dungeon.

I really don't see a factor on why this would be limited. As it is you cannot kick someone from a party and if someone leaves well... tough luck. Can't finish the dungeon unless you want to attempt 3 manning but most dungeons are so finely tuned this isn't possible no matter how good your party is.

My suggestion for a fix... let us add people to a party after someone has left or at least allow a party to supplement with duty finder.