Just looking at these suggestions (sorry either missed these replies or forgot to answer before). Doesn’t look like @Riko is active much here at the moment but since I’m updating this tool I did have a look into this.
The on/off switch would unfortunately not be easy to implement as renoise natively doesn’t have a way to bypass automation. You’d have to trash it and rewrite after or do some hackery with cloning devices. - I can see It would be a nice feature if easier, particularly for MIDI controller use.
Writing to the pattern editor is another thing I’ve looked at but due to pretty much “any fx possible anywhere”, things can get pretty out of hand easily - I’m having a go with this in ICHS but not sure how reliable end result will be. The difference with that tool though is that you specifically select columns to be working with (as part of normal workflow)
re: the [G] button suggestion for native effects still doable. If Riko or anyone is interested/ would use it, I could still add it?