Sorry I thought you had read my
Guildleve idea (Clicky) and was commenting on that not what I had posted in here. ^^
But basically I think my idea solved pretty much all the problems of the current Guildleve system and also some of the new possible exploits but you did bring up a new one of people leaving the party to hand them in. The way I see it is if it is a total at the end and the mobs are spawned as they are now then that pretty much end that problem right there.
Lets use Dunesfolk as an example (sorry just think everyone is familiar with that one) So you get to the last light which you know has the Peiste and you are in a party. If disbanded there would still only be one light to spawn the Peiste to finish the Leve and as soon as it dies the Leve is auto completed so you can't kill it then disband. Only the person who started the Leve can pop the Peiste if the everyone disbanded so the other members would be unable to complete the Leve and get the credit so it would be pointless to try that approach.
I do like this kind of discussion and I wish there was more of it, coming up with ideas to help the game as opposed to just complaining ^^