No matter what you choose to do, make sure to pick up some Embroidered Tippets when you reach Old Archades, as they give you double EXP, which can help catch up lagging members, or hasten the leveling of your chosen party of 3.
Then again, Knegative is totally right, it is a preference thing. If you’d rather have 1 super-strong team, thats entirely up to you.
But alexrider has a good point as well, if you have a super-strong team of 3, what happens if they fail? Unless they’re almost invincible, you’re practically digging yourself into a grave.
The basic Gambit Ally any Phoenix down on all characters really makes having a balanced party moot since Items like that espically if it is on the top of the list happen almost as soon as the character hits the ground.
I have only had problems in 2 areas Level death spells and Zodiark’s special. Zodiark because his special can randomly kill one two all or none of the onscreen characters. While Level death only work if the characters are all the same level just have them each different levels and no problem.
So really just play as you want.