Uh, to be honest, I don't think that CT needs to be further improved in terms of party play because it is still difficult unless you have the new HoL gears. It will only hurt the economy of the fragment rewards furthermore, and I don't think there's merit for it to be done in a full party of 12 people because the mechanic of the instance itself will benefit the party with fewer members.
Maybe try to suggest creating a new custom version of CT, which is so challenging that it is advisable to do it with a big group of players or a party. Then, as for the rewards, it could be costume-crafting related materials (anything that will give the players the reason to do a very hard version of the CT we have right now). Well, for me, it's up to the management on how they reward the players who will do that version of CT.
So I do -1 for this, but I'm +1 if a new version of CT will force us to do party plays and weird mechanics.
Have a good day, everyone.