It so happens that there's no point in taking out a warrant against the man-in-the-middle, because he has no access to begin with.
You'll have to get a warrant against one of the ends.
What these proposals would end up doing is to force people to weaken protocols and start spying as a man-in-the-middle, just so that they can be targeted by a warrant.
This is just a little bit silly, I feel; and doesn't really help anyone. I don't think that authorities realize that that is what they're asking for. Usually when it gets explained to them, sooner or later they relent. And then a few years later someone replaces them, and it happens all over again.
So how decides when an attempt is just? Did the British think the American revolutionaries were just in declaring independence?