from a database implementation perspective, the kind field creates an extra factor in a factorial combination of fields that the user can search on, that's why i want to do away with it.

kind specifies a protocol - the combination of an application, and an encoding, right? all messages need this anyway. mimetype: text/plain would be all you would need to describe kind 1 notes. other things might be more complex, like long form, you would want to have text/markdown or text/asciidoc or text/pdf or something, but again, you would have to put these somewhere anyway, it's not like it would be logical to leave out the document type. most event kinds are just document types, some include encoding, some include application/protocol stuff.

so, i'm just saying, kind is mostly redundant, and even already some event kind specs already are redundant by having a kind, as well as these more detailed things in the tags that are part of the kind definition.

65536 possible encodings/document types/applications is very restrictive and not at all future proof.