Possible, but there isn't too much in WoW outside of direct magic that can't be likened to real world physics. Gravity exists (we fall when we jump), and tides rise and fall (we just don't see it in game) as expected for a world already supporting two moons.
The size of the planet is more what determines Argus' gravitational pull, not its current state. A large enough asteroid passing by Earth can throw our tides into chaos as well, which is why movies like Armageddon aren't super realistic in their theory that just preventing impact would save us. There's a minimum safe distance that a celestial object has to pass by for us not to care, which is determined by that object's size and the speed at which it travels relative to our own. IF the gravity can affect us through Illidan's portal, the fact that a planet at least as big as our own and there constantly will have varying consequences, as I mentioned in my post above.