Carbuncle actually looks like what's it's meant to be a classic Final Fantasy summon in shape and form.
Garuda, Ifrit and Titan are just deformed floating gummy sweets that barely look like what they're meant to resemble.
XIV imo has the worst incarnation of summoner because of this, if I had it my way I'd make each individual summon act like its own ability much like how Yuna summons in the second Dissidia game.
I'm sure there's some people that like the egi's but they don't do it for me. :c
