i do not ever record automation into REAPER using any of the latch/write modes, because i never, ever want this to happen:
if i'm recording AI, i'm trying to record a specific sweep or movement.
i'm never trying to layer multiple envelopes to effect each other. not once have i used overlapping envelopes of the same type. i see the appeal, but this function seems unimportant compared to the ability to overwrite an existing AI.
the expected behavior would be this, where existing AI is overwritten by your decision to record into the envelope:
compare REAPER's AI envelope recording methods to its MIDI recording methods. currently, the behavior would be comparable to the MIDI editor always being stuck in overdub, rather than being able to overwrite existing data.
this issue can be resolved by giving me an option to DISALLOW overlapping AI of the same envelope. i'll never need it. i'll just create the envelope shape i actually want, rather than using one to modulate another.
seems like option: "disallow overlapping AI on same envelope" would be easier than changing the automation write modes. it would also solve issues like this (move envelopes with items toggled ON):
this is a mess. it often happens unintentionally, if track volume automation is enabled but not visible. i'll end up with tiny AI scattered throughout the project -- often very difficult to see.