"Forgiving" is a very good way to describe this headphone's signature, actually
It smooths things out, so that nothing ever seems to sound harsh or fatiguing.
I wouldn't really go so far as to call the bass of the MDR-1A "bloated," as many people seem to do. It is boosted above neutral, for sure, but not bloated. One interesting thing about the bass-boost of the MDR-1A is that when compared to a perceived-equal-loudness-curve, the bass boost is only in a very narrow bandwidth extending from about 60Hz to 180Hz.
It's not ESPECIALLY "dark," really. Sure, the upper-mids and low-treble are recessed, but I've heard MUCH worse, in that regard, from many other pairs of closed-back over-ears which are supposedly at "audiophile-level." And it's better to have somewhat-recessed upper-mids/low-treble than to have stridency or sibilance (or both), IMO.
All that being said, I would still agree that classical, or anything else all-acoustic, is the weakest genre with these headphones. I prefer listening to classical or other symphonic or acoustic music on my Trinity Delta IEM's, which are not dark and don't have recessed highs and yet manage to avoid sounding strident or fatiguing.
For all other genres, I love my MDR-1A, though
For rock, rap and hip-hop, jazz, etc., it's just great
And I would NOT say that it is by any means "bad" with classical, just that it could maybe be better if the bass were about 2 to 3dB less at 100Hz and the highs were about 2dB higher. To me it's not that big a deal, and I still think that classical sounds very good with it.