I tried to play the Witcher III on Blood & Broken Bones last night, and couldn't get past the first ghoul encounter with Vessimir.
One can quibble about difficulty levels but I personally believe the fact that W3 has compelling plot and characters (rather than procgen nonsense) to be a more fundamental difference between the two games than the difficulty level. Of course that's just a matter of taste so debatable.
Ultimately any video game will become easy with enough practice (barring a few rare games with a very high degrees of randomness). For some games the level of practice required may be so absurdly high no one bothers, but it's still true. This is just the nature of games with predictable behavior.
For games with unpredictable randomness, such as FTL, even then there is usually a "best play" method that is statistical in nature and players usually figure it out (often incredibly tedious). Some games combine the two.
So for me any challenge in ED must come from either BGS manipulation (which is indirect PvP) or combat. I find the former tedious and opaque - thus it's pew pew pew for me.