Hey frozst, nice to see you here on head-fi so we can continue our discussion from xda-dev forum ;)
As I mentioned to someone else's comment in xda forum, I wish I could compare W40 to W4R but I'm not in such position, at least not yet. I remember my initial reaction to W40 was similar as yours, you can probably go back a few pages to read it. But after 10hr of burn in (using pink noise loop), the sound drastically improved with frequency spectrum becoming more balanced and detailed, and mids being less scooped. Perhaps mine got burned in faster, and yours is taking longer? I have been listening to W40 quite often, and still compare to UE900, and with every listening UE900 goes down in my sound preference. I can tell you with certainty W40 are not bassheavy, and low frequency will settle in. I have tested and compared M-Duo, CX 985, and ATH-CKX9is and those are bass-y with a v-shaped sound signature. W40 is nowhere near in terms of their bass. Also, UE900 are too mid-centric and sounding thinner in comparison to warm sound of W40, but in my opinion they offer a similar level of details just a different shape of spectrum. Sorry, I know I'm not much help since we are talking about W40 vs W4, and I only have other IEMs for reference. Btw, I also using only EPIC cable.
Hopefully with more people moving to the new W-series we can get more comparison feedback. And I hope with more burn in yours will improve? I know I sound like a fanboy, but I'm just enjoying these too much after so many other headphones I have listened to.