Without meaning to offend you,
I trying to figure out why you think your post would offend me! In fact, I hope I don't offend you with my reply; hopefully you're not as sensitive as the OP!
but unless you have participated in a masterclass of someone like, say, Dimitri Bashkirov, you cannot really judge about the difficulties in certain little treasures by certain composers.
Bashkirov is an absolute legend. I'd wager a lot of money that he has made Volodos feel worthless. I'm jealous that you got such an opportunity!
Anyway, to address your comments: Why does participation in a masterclass assume the ability to judge difficulties of pieces? Sure, the majority (or perhaps even all) of the students who participate in these masterclasses also have the ability to judge a pieces difficulty; but I think it's silly to make any more assumptions.
I believe that participation in a masterclass with a world class teacher is independent from being able to read through a piece and judge its difficulties. However, I do believe the reality is something like this:
-Students Who Participate in Masterclasses with World Class Teachers: {a1, a4, a6, ...}
-Students Who Can Judge a Pieces Difficulties Accurately: {a1, a2, a3, a4, a5, a6, a7, a8, ...}
I did the "comparatively easy" Rachmaninoff prelude op 32 no 12 with him, and I felt completely worthless during that process. That little piece turned out to be much like an oversized raincoat for me. 
Out of curiousity, what do you mean by those quotes? I'm taking it that you're using the quotes to indicate sarcasm, meaning you think it's actually difficult. If so, I don't think comparatively easy needs those quotes. If you put that prelude next to Rach's 2nd Sonata, there is no way you'd consider the Rach Prelude hard. In fact, if you gave me that prelude and any Mozart Sonata, I would definitely need to spend way more time working on the Mozart Sonata.
Honestly though, I find everything difficult -- even the simplest Chopin waltz or Mozart sonata that's easily sight readable; however, the simplest Chopin waltzes could be memorized, polished, and ready to perform in a day or so while something like a Scriabin Sonata may take me more than 3+ months to just bring the notes to tempo because of the difficult rhythms and the technical obstacles to overcome.