I think things have gotten a bit better with my burn in. I've found that those flat vocals still remain to some degree, just with those recordings. If anyone here listens to hip hop I like Tech N9ne and Strange Music a lot, but their recordings don't seem to do so well under scrutiny. Deep good bass is not a common occurrence, nor does a spread out/well mixed soundstage seem to be. And the vocals have that airiness to them that bothers me.
Other recordings have a nice wide soundstage as well as depth, which I haven't yet really experienced with my Sennheiser HD650s (the depth). Maybe they need a better source/supply chain to shine (one definitely can do better than an Audio-gd Compass integrated $200-300 dac/amp) but $60 portables that can do it over sub-flagship ~$350 cans definitely says something