As always, "it depends."
For existing software that's already using Flash, then it could make sense to continue adding training modules in Flash. The gist here is that you would be extending some sort of an existing application.
For new software, you can certainly use Flash, but it may not be recommended.
On the plus side, there's a lot of existing material already out there for creating an application in Flash. Most problems in that space have been solved at least once by someone else, so development time could be quicker.
Over the long term, it's probably a losing proposition. Much of the computing market is moving towards smaller, mobile devices where Flash is a persona non grata. That means a potential target audience is going to continue to shrink over time. However, your target domain may not care about that aspect.
Adobe hasn't killed off Flash as a product line, although it has trimmed back deployment platforms. AFAIK, they haven't announced its death so there's easily several years of life left in the technology. Again, what your application requires for longevity will dictate whether or not it's wise choice.
It's unlikely that Adobe can fix the underlying security issues within Flash, and it's very unlikely that they can fix the perception. HTML5 + associated codecs will likely step in as a replacement.