Could Xal'atath be Y'shaarj?

I did not see that. If you look at the others, they have something similar around them that describes where they are.

N’zoth is surrounded by waves, as he is under water.
Yogg-saron is surrounded by mountainous spikes, hinting that he is in a mountainous region, but also the saronite spikes (his blood).

Y’shaarj has a body like a cloud serpent, whom are native to Pandaria (where his heart was located) and C’thun has the monoliths of AQ near him

I like your mind set, because i think we beat the old gods to easily personally, but i subscribe to a different head canon on yshaarj. Granted shadowlands kinda debunks some of my theories.

My theory boils down to: sylvanas is attempting to revive Yshaarj. Its mainly her talk about even Nzoth dying will serve death and that whole speech.

Now my original theory was that Yshaarj told voljin to make Sylavanas warchief. Where was the last place voljin was mortally wounded? Pandaria. Maybe he somehow got infected by Yshaarj.
Plus, his wound had an aura similar to the sha if i remember right. So the logic worked in my head.

But, now with the jailer being a thing, im pretty sure he was the one who whispered to voljin. Now its still possible the Jailer wants to revive the old gods, but that has yet to be determined. Or mayby sylvanas is using the jailor to get the power to do it on her own.

Its a pretty crazy theory, but I really feel like we beat the old gods way to easily. I want them to return in full world/universe threatening power.

Xal’atath is simply a void being.

C’thun was too busy keeping hold on 3 very powerful dragons and was just recently released. Yogg-saron had to deal with Thorim in some way even after getting released by Cho’gall. We also had the four remaining keepers of Ulduar helping us against him. N’zoth is the first one we actually face who is truly free. We face him within his own personal realm and we actually struggle to defeat him.

It still feels to easy. I mean they are arguably worse than the legion who got practically 3 xpacs dedicated to them, and we didnt even technically kill their leader.

But we are able to beat all remaining old gods with no world shattering events? (Ok cataclysm can be chalked up to Nzoth i guess)

To easily defeated. I really hope this is the “end” of the old gods and not a true end.

And have to reduce him to his base elements to do so and who among mortals knows what effect it will have on Ny’alotha’s ecosystem!

The Twilight’s Hammer(with the help of the Forgotten One Gor’ma) will have their hands full studying the distinct Void Magics of N’Zoth within Ny’alotha during our time in the Shadowlands.

The reason why the old gods feel more of a danger than the legion is because they are already here on Azeroth. The Legion has to be summoned every time they want to invade.

However Legion > Old Gods in the lore. It is why Sargeras and the burning Legion were the primary antagonists of Warcraft from WC1 to Legion.

The old gods were always the secondary antagonists, with N’zoth being the primary secondary antagonist due to expansions like Cata and raids like the Emerald Nightmare (which yogg originally created, but N’zoth was the one who actually did anything with it).

Perhaps the tree that was ripped out by the same person in the same area was in fact Y’Shaarj? Meaning the 5th was possibly planted by Eonar.