I thought the M5 feature list would make a great 6DII... without a mirror....
All I can say, is that there are options in the $1000 to $2000 range that have features that would blow the mind of anyone in the market for a 20D, or even a 50D.
If you can limit the size of the sensor to APC (50D) and are willing to trade off to the MF4/3 both Pany/Oly offerings are just chuck long in features (who knows if all of them are useful).
Here is a wild statement, if the M5 had 4k video there would already be one on my desk, with the two kit lenses and my 5dIII donated to a local highschool or something. Particularly if Canon would reverse tele an adapter ala metabones. As an enthusiast that would give me all that I could imagine.