I will never get how ANYBODY would generalize and consider the entirety of the HE-400's midrange as recessed. 2/3s of it is forward, and somehow it seems as though people think the last 1/3 of it-- the area from 3-5khz, as enveloping all of the midrange. That's the feeling I get when I read remarks like yours. I think David Mahler categorized HE-400's midrange the best.
As for the bass... well. I don't really know what to say.
I also don't really know how you could consider the Magni to not be able to drive the HE-400 to loud volumes without bass distortion. If the Magni is at 9-10 o'clock it's already loud enough for me and still never distorts.