would it be a good practice to standardize on the use of the flash ram
as way to handle all messaging, thus superseding the need to use the
messagebox plugin at all? or does it still have it's role or purpose?

i sort of like just dumping this at the top of all my views for
errors, info, or just whatever....

<cfif flash.exists("notice")>
  <div class="notice">#flash.get("notice")#</div>

is that a good idea?

It’s a matter of choice. The message is a convenience