i dont tihnk theres one absolute best. everyone has their own style. some people prefer more defensive parties, others more offensive or supportive parties.
most of the weapons are pretty well balanced against each other, so when you bring them into the picture things only get more mixed. i dont think youll have more than a couple of people agreeing to any single setup.
if you want to beat the last boss, just grind more skillpoints.
I'm not sure if this is the topic to ask it, but in my mind it sorta relates. Is it possible to max out every Skill Set and Vocation with your characters? That would be great because it would really give you the flexibility to use whatever you want whenever you want. --- Throw away the impossible~! Kick Reason to the curb~!!
4 Gladiators. One with Gritty Ditty and a Stardust sword (lowers defense on hit), another with Group Force buffs and a Stardust sword. Falcon Swords on the others. Similar agility all around with the buffers having more.
Feel the burn x2 and your buffs on round 1, eat the damage. Turn 2 everyone uses falcon hit for your delicious 1.5 and 2.0 combo multifpliers to a full defense down'd boss. Doesn't work on the few bosses faster then you, well it can but they might kill you in turn 2.