It's no doubt a solid headphone, but there is definitely some room for improvement.
-volume knob is a bit weird. There is almost no change in volume between some clocks on mine, e.g, 9-12, 1-3. I read this happen to a lot of ppl.
-no remote. A bit inconvenient when use as a preamp.
-low gain is still too high for some headphones or iems unless you send it back to Bryston for a mod
-no 4.4mm output
-no RCA outs
-3.5mm input is a bit outdated. This was designed mostly for input from old cellphones
-it would be great if there is also a 12v trigger out. Better use 3.5 mm version instead of the Phoenix plug
Every headphone amp has room for improvement, many of the stuff you listed are rarely found in one device. Exceptions to 2-channel pre-amps or integrated amps.
Volume knob: this is deliberate not a design flaw
No remote: I have 6 headphone amps, on the only one with a remote was the TT2
Low gain: any full size amp will be too much for IEMs, they are too sensitive! Full size headphones, sure there are some and more exceptions. If the Bryston is too much for them, the better solution is probably an amp or dongle more suited for their sensitivity.
4.4mm: outside a DAP, never owned a headphone which had this
RCA Output: Did you know that the Bryston can convert Single-ended into Balanced to work with another Balanced amp? Useful feature. Also, not all amps have any pre-out, some rarely have a pass-through output. The balanced output adds the ability to use the BHA-1 as a pre-amp
3.5mm input: it’s still an input which can be used, RCA -> 3.5mm cable
12v trigger: Which other headphone amp provides this? Probably less than 10.
I still disagree, and we don’t have to agree at all. If you enjoy it, great. If you don’t, great. I don’t think it’s fair to call it outdated when many of the features you listed are more along the lines of kitchen sink do it all. Might as well throw in a network streaming DAC too if we are adding features
In the price range this sells for you are asking for a lot of nice to have stuff, none of this is must have. Maybe a Holo Bliss, a $3.5k+ headphone amp has most of these options, sure there are others. It’s a bit misleading to nitpick these things as needing to be included. My best amp is a crap ton more expensive, has two inputs one headphone output, doesn’t like IEMs or sensitive headphones ( I barely get past 2 on the volume knob), but man it sounds fantastic. My point, we all place value on different things with a piece of gear. At the end of the day it’s a matter of what one is willing to give up for the sound.
Everything else is just extra
