Is it that easily avoidable? A lot of AWS's control plane seems to have dependencies on us-east-1, or at least that's what it's looked like as a non-us-east-1 user during recent outages.
I remember a Workspaces outage about 5 or 6 years ago, and the problem for us was that the redirect link in the console had US East 1 in it.
The workspaces themselves weren't in US East 1 and nothing relied on US East 1.
Emailing users who needed it an alternative link with a different region in the URL for the login redirect fixed it for us.