assuming they are all maxed, does that team have issues w/ any story quest? I would think not. If you don't have a tank, good to have one on stand by as some events require it. my RL friend who plays is F2P and doesn't macro, so he doesn't have good dps. To beat events he has to min/max like crazy. To get the no-white magic 15%hp materia last event, he had an all tank team, Ling and Primm, and the fight took over an hour, over 100 rounds. Araxis dragon from the event prior took him almost 3 hours. If you don't have a ton of TMRs yet, tanks seem to get you through events better than magic or physical dps.