The only option in Advanced Settings for MixMonitor is to use it instead of Monitor for Queues. Regardless of that, you’re conflating the modules that Asterisk loads/installs by default with the Asterisk modules that FreePBX uses. There are third party applications out there that those with FreePBX use with FreePBX, such as FOP2 which still uses Monitor over MixMonitor.
Let’s not forget what happened at the start of this year with the removal of app_fax in v19 which broke faxing for FreePBX users that upgraded to the v19 RPMs. app_fax was set to noload almost a decade ago meaning FreePBX had to specifically tell Asterisk to install/load it to continue to use it for fax in FreePBX until they couldn’t anymore. I mean, app_macro has been noload for four years now and this project still heavily depends on it.
So yeah, I think letting people know what is going on considering the amount of 3rd party applications still behind the times. People with custom code/scripts who haven’t taken the time to modernize them plus all the out date documents/how-tos/code out there for these things (which can still work despite not being used by FreePBX itself) I think keeping people up to date on things is a good idea.