Very disappointed by this news, I was really looking forward to new Egis, alternate skins or not.
It really feels like they totally changed their mind on where SMN was going and Egis now feel like an abandoned half-attempt.

The glamour system could really help us in this regard since they could basically add an Egi everytime a new primal comes out without having to wait expansions or patches, all of this without having to think too much on balancing reasons.

It could be something like this:
Caster Pet: Emerald Carby - Garuda Egi - Ramuh Egi
Tank Pet: Topaz Carby - Titan Egi - Shiva Egi- Bismarck Egi
Melee Pet: Ruby Carby - Ifrit Egi - Leviathan Egi - Ravana Egi

They would act in the same way our current egis do with just different skin/attack animations, SMN would get to summon something else without altering game-balance.

Hopefully devs can work it out in an elegant way and yes, the lv50 troll quest was evil and not nice at all.