With a perfect seal, my 5 year old IE800 have no mid-bass bloat whatsoever, just a steady rise from lower mids down to sub-bass. However, a perfect seal isn't easy to achieve with these tiny IEMs. If your seal is ever so slightly leaky, then sub-bass is the first thing to go and the IEMs will sound more mid-bassy. Now, I'm not ruling out product variance for the IE800, but tend to believe that most people who hear mid-bass bloat don't get a perfect seal.
In my direct A/B comparison, bass characteristics on the IE800S reminded me somewhat of an IE800 with a slightly leaky seal. I heard the main bass emphasis consistently in mid-bass, and even with a perfect seal on the IE800S, could not coax sub-bass comparable to the old IE800 out of it. My understanding is that they deliberately tuned down the sub-bass just a little on the IE800S. And if you up the volume a notch to achieve similar overall bass levels between IE800S and IE800, you'll end up with a warmer and more mid-bassy sounding IE800S as compared to the older IE800 (both with perfect seal).
Anyway, that's just one subjective opinion, but maybe it helps to shed some light on these seemingly conflicting impressions...