I never change Tidus's name. It'd be too weird to me.
; Though I have thought of calling him Pacman XD
I ALWAYS change the aeon's names, though. X3
For example, in my most recent game(that I CANNOT BEAT THAT FRIGGIN' SEYMOUR FLUX, DAMMIT >.<):
Valefor-Suika(watermelon
)
Ifrit-Hanabi(fireworks)
Ixion-Hana(flower)
Shiva-Rin(cold)
Bahamut-Kami(like, God or something)