I see what you mean, but I do not think that LCOM4 is used to measure individual methods, but rather groups of unrelated methods/fields within a class.
The thing is that, before we made those few changes on the way LCOM4 was computed, there were way too many false positives, and nobody was actually using this LCOM4 metric anyway.
Now, at least, the metric is becoming useful as it is able to pinpoint exactly classes where real problems occur (and so now we can indeed think of a rule that looks for classes whose LCOM4 > 1).
If we make any change to the way this metric is computed, it will be to improve it, and not to get back to the original situation where this metric was absolutely useless.
So now, if we want to revert this ticket, the challenge is to not introduce all those false-positives back. One would have to be able to clearly specify what those cases are.
If an instance method does not access any field nor any other instance method, then it should probably be static.