More and more I'm seeing—or perhaps imagining—writers declare in their query letter that their story is told from "multiple points of view" or "alternating points of view," as though it's a selling point.
At the query stage, do agents want to know this?
Well, it's not really a selling point for me, more of a red flag. I think writing multiple points of view is really hard, and not very many people do it well.
And often, multiple PsOV could be solved with an omniscient POV, but prying people out of first person POV is like getting the dog in to the tub:
Which is to say, I do like to know about it in the query cause I know what to expect. And if they tell me it's seventeen PsOV, I can just say no to the query and save us all some time.
Which is not to say that multiple strands of a story is something I would reject out of hand. I LOVE those big sprawling books that follow all sorts of characters as their lives intersect and carom off each other. I'm reading one now: CITY ON FIRE by Garth Risk Hallberg that is amazing.
And Bonfire of the Vanities?
And Airport, Hotel, and everything else that Arthur Hailey wrote?
All of those are in the third person omniscient. Not a first POV to be found.
So yes we want to know, but not for the reason you thought.