I have similar thoughts. I already used wifi-bar-like signal to indicate the seen relays for notes on https://flycat.club/, will impl relay-specific feed later 
Put my money where my mouth is and implemented my relay "layer" in dialog form. You can now see colored indicators of which relay(s) a given note was seen on. If you click on one, Coracle will open a modal with the same feed you were looking at filtered down to just that relay.
The idea is that this will give you an idea of what kind of content differentiates relays from one another. See it in action below:
https://dufflepud.us-southeast-1.linodeobjects.com/relay-overlay.mov
https://blog.coracle.social/posts/2f375ecdcefa65f5d7d9ae5b74f3d276a6e2b2c9a4aafad50c48cc6be66407b2
# Version 0.2.23 changelog
- [x] Fix modal scroll position for nested modals
- [x] Fix memory leak in pool.subscribe
- [x] Use relays specified in bech32 entities
- [x] Add colored relay indicator to notes
- [x] Add relay-filtered overlay dialog to feeds
- [x] Improve relay detail header
Discussion
That's a very interesting take!