I'd like to just suggest to the devs to just implement a glamour system for all summoner summons, even if they can only add 1 at a time. Start out with Leviathan as a glamour replacement for ifrit, titan, and garuda; he'll just do the same damage those 3 already do; the only difference would be visually. Interestingly my friend told me a modder was able to do this; it's just a matter of copy pasting the model and its attacks.