otherwise quickly identify (a) passive vs active abilities
Isn't that the golden "elite" dragon border? Or are you talking about something different?
as well as (b) highlight active spells that are not on any bar.
There would probably be a lot of false positives from macros containing the abilities (e.g., spell+/startattack), but the audience who would be using those macros is probably a disjoint audience from one that would be confused by the warnings. :-)