Why do the Egis appearance look awful and unimpressive

[Exodus-E]

Summons first appeared as we know them in FF4.

Uh, no.

The Summoner job (thus, the summons themselves) first appeared in FF3.

But if you want to be get technical about it, Bahamut's first appearance was back in the very first FF, while Leviathan's (kind of) first appearance was in FF2.

So yeah...