They need to chop up the old towers into individual bosses and put them in trial roulette. As much as it would suck to not be able to run the towers in their original format through random duty finder, you pretty much already have that situation. They can make the optional 4th chest randomly spawn on all 4 bosses of each tower, so you don't have people just spamming the last boss.

I would love to finish one or two of my Syrcus Tower glamour sets, but waiting for an hour on a specific class (so I can roll need), just for the group to fall apart before we reach my boss, only to reach the boss on my third attempt and not see the loot drop... Crystal tower is just a waste of time as it is now, adding new items to last boss won't help.