Keynotes
I have been fond of keynotes for years (decades). I think they are a time saver, improve the drawings, can be helpful to bidders/contractors, prevent conflicts, and in some ways can act as a checklist of things to include.
The ideal system would have the same note number throughout the drawings for the same note, but would only contain the notes on a given sheet that apply to the work shown there. That note number would also contain the spec ID for the work involved. This automatically shows who is responsible and lets the keynotes become the specifications. An example would be "04810 - A: Modular face brick with Type S, concave tooled, mortar joints."
There are times when a lengthy note describing an assembly of many discrete items of work is useful. This doesn't lend itself to keynoting. I suggest a General Note, and simply write it out.
Another feature of the ideal keynote system is that you can save every note ever written in a kind of database for use on the next project. A checkbox includes it on this project.
The applicable notes need to be on its drawing. It is inexcusable to force all the viewers of the drawings to flip back and forth or find them in a booklet. If they are on each sheet then they have to be limited to only the notes that are used.
Meeting all these criteria gets complicated, particularly maintaining a database while using the database on more than one project at a time. But it is do-able.
If your expensive CAD program can't do this, you have to wonder, "Why not?".