Personally, I didn't like the large number of characters. I focused on levelling up 4 main people being Celes, Terra, Sabin and Edgar. When I was in the last dungeon and I had to struggle through with the under levelled characters. Most FF games tend to let you level up a small pool of characters and stick with them with some small mid game sections (e.g bevelle in FFX, 4 crystals in FFIX).

End game dungeon with 8 under levelled characters though? No thanks.