Whoa, I wrote the same thing to them via email. They suggested I write it here. Here’s what I wrote them:
“What I’d love to be able to do is when an email is highlighted/focused, I’d be able to type a keyboard shortcut like (CMD + Shift + F) or something like that and the current email list would be filtered down to only emails from that sender, no typing necessary (quicker). I can then choose to select all and possibly bulk delete, or I can select specific emails and do what I want with them, and leave the unselected ones untouched. Then once I’m done dealing with that sender, I can enter the same keyboard shortcut to exit that filter and the full email list would appear again.”
The way I image the sender’s email to be displayed to show what the list is filtered by ISA in the attached photo. It uses a view that Newton already has.