If a client sends a REPLY to a case email (which is from an "email to case" email address), can SF not be told to send a copy of the email and/or send an alert to the Case Owner? This seems no-brainer to me, but I'm not finding help for it (Google, Community, etc). Otherwise, a Case Owner would need to check the case periodically manually to find out if any replies have come - this seems silly.
AFter finding no help online, I did some experimentation in SF, and without having to write Triggers (that is not my first preference usually) it seems that "Email Message" which is related to "Case" is available for Workflow logic. I'm checking this out as a viable solution now. STILL LOOKING IF SOMEONE HAS SOMETHING BETTER THOUGH.
UPDATE 1: I note that to make it work with Workflows requires two of them (as far as my skills show). One to mark a field on the Case temporarily when an email arrives, then another to see that mark, send the email alert, and clear that marker field to be used again.
Next focus is to make it so the INITIAL EMAIL does not trigger this workflow (since we have workflows for various email-to-case / record types to send a "thanks for the email, client, we'll get back to you") OR perhaps alter the existing ones to include a second marker on the Case that would get marked when processing the initial email-to-case to bypass what I've done (and then clear it later). Not sure yet......
One shortcoming - I do not get access to the EMAIL FIELDS on the email that fires this workflow since the SECOND workflow is a CASE flow.
UPDATE 2: I will have to update all my initial-email workflows sent back to the client, but this is definitely the right solution to avoid having to go to Apex.
Thanks @User320 for your input!