Training on Apex is definitely needed. I'd be more interested in a practical course where I could learn different coding techniques and tricks of the trade, and best practices.
Your target audience are mostly going to be Oracle developers familiar with SQL and PL/SQL but not familiar with HTML and JavaScript.
Typical things I'm finding difficult are:
How can I reference a javascript variable in my SQL statement?
How do assign a javascript variable to a page_item?
How do a read values from a URL and autosubmit the page using values from the URL?
Basically for me, A training course would need to have more of a developer bias, and a practical course would be essential.