Did LL roulette as a tank. Had i90+ MNK and i90+ BRD in the group. Yes, level synced.

Figured that hey, super beefed party, shouldn't need to mark since they should be street smart and attack the same mob when a small pull was done.

Nope. Only when I started marking. And even then, only when I finally just let the BRD have his/her #2 marked mob and almost died did they finally coordinate and take one down at a time. Sometimes people just want to learn the hard way.