Is it possible we'll get another servant class?

Because I've been thinking, we got Foreinger's in the Salem chapter and Pretenders in the Lostbelts. But the question then arises, what would this new class be? It'd have to be introduced in part 3 of FGO, but what would it be? Is it even possible to add another class? Who'd be it's first representative? And what would it be weak and good against?

An idea I had is maybe some kind of embodiment class? Or representative class? For example, you could have four servants represent the four seasons maybe you could do it how captain Nemo is a mix of people? Or I feel a Pseudo servant would be a better way to describe it. And what about other concepts?

The concept class? Maybe introduce Hollow Jack to represent Halloweeen for a Halloween event? Only problem is we already have servants themed over these holidays so they can't be put into this class.

So my suggestion is this. I don't really have a name, so I'll go with Embodier. The Embodier class represents the inspirations and creations of humanity, their spark if you would.

You could have Hollow Jack represent a concept like Gap Moe or like I said before, Halloween, how even fear can be inspiring. For a Winter servant you could do Jack Frost. Then have one for spring, Summer, and Autumn.

Maybe have someone like Louis Cyr to represent strength? Humanities inspiration to become stronger?

As for strengths and weakness. I feel the best way would be to take all 4 match up charts. And have them be weak to one, strong against one, and neutral to one.

So for example;

Strong against; Saber, Rider, Ruler, Berserker and Foreinger.

Weak agsinst; Lancer, Assassin, Avenger, Berserker, and Pretender.

Neutral against; Archer, Caster, Moon Cancer, and Alter Ego.

Only problem is it'd need a class to be it's opposite. But I can't think of anything, or a third class. I feel it'd need an opposite for balancing purposes.

Is this a terrible idea for a servant class?