I like the balance that you've struck between being discouraging and encouraging. :D
I think it's a bit much to understand for someone that isn't familiar with the project. Maybe it makes sense to be more explicit in telling people to answer the points/questions in the last section as best as they can and ask in the forum if they are unsure about the downstream effects of their proposed change. But that could also mean more burden on the volunteers, not sure.

Where would this document be linked from? I guess it's something that can be sent to someone that proposes a change that doesn't consider those issues. But how would we maximize the chance that people read it before they submit a proposal?
It could be linked to from an issue template on GitHub, is something similar possible in the Discourse forum?

If anyone would like to add a commit doing the config.json work for me too, I’d be grateful!

I don't think I have ACLs to push a commit on this branch.

commit 4dfba77ba6a9be4d0ceba5874231b0fe950f1291 (HEAD -> iHiD-patch-3)
Author: Isaac Good <github@isaacgood.com>
Date:   Mon Apr 3 16:47:18 2023 -0700

    Add a config.json entry for the new "suggesting-exercise-improvements" doc

diff --git a/community/config.json b/community/config.json
index 3267ad7..4eb2b52 100644
--- a/community/config.json
+++ b/community/config.json
@@ -27,6 +27,13 @@
     "title": "Administrators",
     "blurb": "Learn about Exercism's Administrators"
   },
+  {
+    "uuid": "4476a48e-3061-44c2-ba56-56896b1e0dc9",
+    "slug": "suggesting-exercise-improvements",
+    "path": "community/suggesting-exercise-improvements.md",
+    "title": "Suggesting Exercise Improvements",
+    "blurb": "What to consider before suggesting exercise improvements"
+  },
   {
     "uuid": "7e11a8f5-e6f8-49f1-ab0c-81427fa12c5c",
     "slug": "being-a-good-community-member",

Where would this document be linked from? I guess it's something that can be sent to someone that proposes a change that doesn't consider those issues.

Places like this: https://forum.exercism.org/t/go-track-need-for-speed-suggestion-for-a-test-scenario/4974/6

But how would we maximize the chance that people read it before they submit a proposal? It could be linked to from an issue template on GitHub, is something similar possible in the Discourse forum?

Agreed. We should add this to contributing guides of the relevant tracks, check READMEs mention it, and set an issue template too.

Thanks everyone

This doc can now be found (and linked to) from https://exercism.org/docs/community/being-a-good-community-member/suggesting-exercise-improvements