The question is not whether signalling is real, or whether signalling can be pro-social. (It is, and it can be).
Instead, I read the OP as raising the more meta-question of how we can tell useful signalling talk from hand-waving just-so-story signalling talk. I think everyone agrees that the later is not useful analysis. But there does not appear to be widespread agreement about how to tell the difference (or even if very much anti-insightful signalling talk even exists).
Well, one way to start is whenever someone proposes a signaling model ask the following question:
1) What is being signaled?
2) Why is the allegedly signaling behavior a credible signal, either now or in the EEA?
It seems to me that when people discover signalling, they see it everywhere and write essays about how no human activity is aimed at its stated purpose.
However, stated purposes and other sorts of useful work get done anyway, and I'm sure there are constraints which mostly keep signalling under enough control that it's mostly not deadly. When I try to think about the subject, I don't get anywhere, possibly because the constraints on signalling are mostly tacit.
Any thoughts or resources on the subject?