Why are SMNs not getting new Egi?

[Reinhardt_Azureheim]

snip

Good suggestion, but to keep the roots of Summoner true to the ARR style for time's being, I suggest the following glamour options:

Melee - Ifrit <--> Leviathan
Ranged - Garuda <--> Ramuh
Tank - Titan <--> Shiva (in sword + shield mode)

Regarding the "lack" of demi-primals, you need to remember two things:
1.) Even the model of Bahamut took strains to create for optimization. Demi-Bahamut looks fairly different to the real one.
2.) Demi-summons will most likely be based on "Prime" primals, such as Bahamut Prime and Alexander Prime. That said, I can see Alexander Prime being a thing, even if only as glamour to Bahamut.