So I've collected my thoughts about the Dekoni fenestrated pads (I've been listening to them for almost 2 days) and decided to sell them. Firstly - they do exactly what the graph shows, but for my perception with a stronger effect, much stronger than I would like - they reduce the low end, also cut some of the upper mid-range I like, and excessively (for me) boost the upper frequencies (the level of details is the same - only the loudness of these frequencies - just like parametric would do) thus completely ruining the LCD-X'21 character with stock leather pads that I've grown to love.
They also feel about 2 times bigger than the stock pads and I feel like a hammerhead fish

This adds to the bulky feel and I can really feel the weight of the headphones when I move my head around, whereas with the stock ones I hardly feel it at all. After an hour or so they get warmer and softer and it looks like the headphones are clamping them a bit tighter, adding a bit more extra boost for up freqs, but this addition is not as strong as the initial one. They feel cooler and I didn't feel the vacuum like I did with the original, but this bulkiness and sound impact outweighs it for me. They are also stiffer and it takes some time for the memory foam to warm up and get the best fit.
The quality is exceptional, but I didn't expect it to be any different. So overall I don't think they are bad, you just need to know exactly what to expect and what you want from them (like Andrew above), in my case they are a complete miss (I expected this and bought an open box of unused ones from a local dealer and already have a guy who wants to buy them from me). If I had bought them at full price - it would have been an epic fail for me : )
I contacted Audeze with the question about the different softness of the stock pads and they advised me to change the unit with the dealer (which I think is a bit overkill о_О).
I told the dealer that I didn't want to return the unit and just wanted to have the pads to change them myself and they agreed and I'll pick them up today and swap dekoni for them.
So maybe someone finds this useful
P.S. swapping glued pads while you comparing the sound is awful and yes, I've read the article why Audeze still do this.