I very much enjoy the current system it allows the party leader to set things up without putting all the work on them to form a party. I worry that people that want the XI flagging system only want it to be lazy and not have to actively seek out a party. I would say have both but I think if they add the flag system people will just get lazy and not use the party search system.
Edit: Actually what would be nice is an auto join feature, you flag yourself, if you fit the criteria of a party searching then you auto join said party.