What’s your source file? Going to DNxHR HQ might be overkill, especially if you’re starting with a 1080p BD. These formats have “HQ” at the end, but you can’t create higher quality than you start with, even if the files get bigger. DNx is effectively ProRes for Avid.

And I understand what you’re talking about with FFmpeg. It’s a great tool when you know what you’re doing. My point is that anything that forces people to use command line isn’t simple, and would be the last thing I suggest to anyone without a good understanding of how to use command line tools.