Wouldn't that be part of improving global health and/or wellbeing? To me this would be one meta level below the general cause areas.
I have to admit I only skimmed the paper, can you explain to me what "bullet" I ought to bite? It seems like a neutral proposition to say, what if we replace "us" with beings of greater well being.
My best guess is that our intuition for self-preservation and our intuition that killing sentient beings is bad most of the time should make me feel like that it would be a horrible idea? I'd rather throw the intuitions out than the framework, so to me this seems like an easy question. But maybe you have other arguments that make me not want to replace us.
I have a question about longtermism and its use within the EA movement. While I find your (strong) longtermism hypothesis quite plausible and convincing, I do consider some "short-termist" cause areas to be quite important, even in the long term. (I always go back to hearing that "you have to be a shorttermist to care about wild animal suffering" which striked me as odd).
Because of that, I liked that the classic longterm cause area was called x/s-risk prevention, because that was one way to create value in the longterm. I think that value in the longterm can be created in other cause areas aswell, so using x-risk and longtermism interchangeable would be misleading in my opinion. So, is replacing the term x-risk one of your goals with your philosophical work on that issue?