Well, this is particularly unwelcome news. The existing set-up was perfect for my use-case; this change makes it worse than useless - the feature is now a detrimental limitation which I’ll have to abandon entirely. The entire purpose of this endpoint is to check whether a message can be safely posted in a channel - in what world is 50 messages in an hour a valid limit for any person or bot in a channel?
The user_id deprecation is also going to be particularly annoying, forcing more API calls and checks to get the state of a user manually.
My biggest question is - Why? Why were the limits chosen to be those numbers rather than something more along the lines of actual messaging limits? Why was user_id deprecated if the internalized calls will just have to be externalized, resulting in the same (or heavier) server-side processing anyway?