I understand your issue with the cable. The cable used on the he-4 is much better and should be included on all hifiman headphones IMO. I'm not sure what happened with the bass for you. The he400 has some of the bass you'll find under $1k. The headband can be bent to give you better clamp and seal which may have been the issue. 
 
It's certainly a popular hp at the $400 mark but obviously not for everyone. 

Lol, you sound almost like one of the Stax aficionados... 
Can follow you in most things except bass and the lack of full sound, just doesn't seem right to me. Apparently, the HE-400 just isn't your 'phone. After all, I think it is hard not to give it credit for being very fast and good at seperating layers regardless of sound signature (for the price that is). I don't like the HE-400 too much either.

Sounds like you never got a proper fit - that is too bad and probably the key problem. All phones need a proper fit to sound their best, and slight positioning changes can sometimes have an impact. I had to bend the headband and twist the cups for best comfort and results, but I can concede that the headband is the worse part - it causes discomfort over long listening sessions.
 
Most of the subjective description I disagree with - the midrange is prominent on these phones, and they are extremely similar in presentation to my HD-595 which have a measured frequency response that would be be called "forward" (as opposed to 'dark'). The treble spike / sibilance is a non-issue for me except with some recordings at very high volume. At sane volumes, the HE's are what I consider smooth and detailed.  The bass response of the HE-400 is superior to any dynamic I've ever heard - much much more texture and detail. The fact that you note "quantity" and not "quality" as the distinguishing factor tells me you don't "get" the HE-400. The initial impressions of the HE to many is 'underwhelming bass' - until of course they adjust to the sound and try going back to something they thought was bass rich.
 
Anyway it would appear that you like phones with a very different sonic signature anyway. Maybe there are some Denons in your future?

As far as fit goes, I get a good seal, but I do find that the sound changes noticeably with even slight shifts of the earpad . Much more so than with other headphones I've tried. It often takes me a minute to adjust both earpads to the point where they sound the same. I'm not suggesting you had fit problems per se, just noting that the HE-400 are extremely sensitive to position on the ears. 

This review seems spot on with the pair I just got brand new 3 days ago. They sound odd to me. No PRAT. They extend to low frequencies with but with no 'feel'. The midrange is weak and on and on. I just got a new Asgard 2 amp hoping that would improve things, but not much difference so far. They do deliver a lot of detail but have to be (so far) one of the most boring and least enjoyable headphones I've owned. I've got a pair of HD650's coming in next week and am eager to see how they compare. So far the HD650 has been the headphone I've liked the most in the short times I've auditioned them. So far, my favorite go to open phone is my Sony MA-900 which so far seems a more exciting listen compared to the HE-400. My only complaint with the Sony is I find it a little 'dark'. The HE-400's are even more dark but at the same time don't seem to have a nice kick with kick drums like the Sony does. For closed phones still sticking with my amperiors for now for mobil and will probably re-buy the a900x for a closed home can. The a900x has been the most special headphone I've had so far, should not have gotten rid of them.
 
Hopefully the HE-400's will change with a bit more burn in

Citizen-
 
No headphone can make you "feel" the bass, and even when they do the effect is nothing like real speakers in a real room. You can't really hear below a certain threshold (somewhere around 20hz give or take - I am pretty bass deaf starting around 30hz), so the lack of feel is a lack of critical information for your ear. It is unusual for a headphone to have such deep bass extension and speed, and the lack of "tacit" response going along with it contributes to a sense of unnaturalness. A 20 hz wave is something like 40 feet long, also, so there is no hope of changing that when the speaker is less than an inch from your noggin.
 
Anyway, it took 3 days of listening for the HE-400s to start sounding good to my ears, and 2 weeks until I was hooked. If you connect with these, there is no going back! They will scale with better equipment, and a good amp with at least 1/2 watt of clean power should give them plenty of punch.

While I agree with your opinions in some cases, for me the HP is still very good.
Especially for gaming.
 
I assume if you come from better headphones like the fostex, the HE-400 might seem to you a significant step down, especially if we factor the sound signature.
 
Interestingly enought, This HP EQs so well that I have no issues with the treble spike whatsoever.