Lol there is just no variety in how any of them look to warrant these crazy hairstyles. They're 5 white dudes of whom look like the same age and stuff.

Look at FF8: Squall had his sorta spikey hair and fluff. Zell had his spikey hair and looked completely different. Irvine had long hair. FF9 didn't really have humans so doesn't count.
FF12 had Vaan with Tidus hair and Basch. And Baltheir looked pretty different too.

These dudes all look the same with crazy FF7 style hair xD