Generally agree. Except:

Logs that are a “debug diary” are not useless. Their purpose is to debug. That’s why there’s log levels. If you are not interested in that, filter by log levels above debug.

Also, the different formats for fields I see as a necessary evil. Generally, more logs (of verbose log levels) = more good. Which means that there should be as frictionless to write as possible. Forcing a specific format just means that there will be less logs being written.

The json (or any other consistent format) logs seem to be a good idea, but I would keep it to a single debug level (maybe info+error?). So if you want to get wide events, you filter by these log levels to get the full compact picture. But if you are following a debug log chain, it seems a pain to have to search for the “message” field on a potentially order-independent format instead of just reading the log.

TL;DR

Log levels have different purposes, and so they should have different requirements.