What an interesting question.
Kick me out of the Warp? Little Mortal, there are hundreds of insignificant godlings in the Warp: Neocho only one of them, no offense to him.
My Siblings can’t stop the Anathaema from crossing into the Warp. They can’t stop Bela’kor, that couldn’t stop the Eldar from regrowing their own little god of Death. They have no idea what to do with Vashtorr. Do you really think they would have any luck with me?
Believe me, if it were that simple, there would only be one of us long before your concept of time approaches the present, let alone M42.
There is, of course, the idea that gods can be slain, and if the Eldar are any indication, they certainly can be. It has also been an occasion for one god to devour another from time to time. Of course, this is to speak only of “gods” in the Warp. There are others, and I cannot speak for them.
The principle means of “removing” a god from the Warp is to starve him of the thing that empowers him or… as I have said above, to absorb his essence. But this is tricky. You’d think they’d have figured that out by now. But -something- keeps driving a wedge between them. Something…
In theory, the so called “Chaos Gods” should all be burning out and reforming naturally over time anyway. Wax, Wane: that’s the cycle. The problem is that the other four haven’t done this in ages. Best to encourage them, then.
Thank you for an excellent question, Little Mortal.