The way any software released these days, online makes later patches and updates possible.
When was the last time you saw a game, even AAA that worked perfectly on the day one, perhaps way back when they were only distributed on CDs.
BTR7 delivers an excellent audio, both BT and USB, features great build quality, and user friendly physical design and interface.
PEQ, I don't use it, so no complaints from me, if it was utterly important, I'd do a better homework before my purchase decision and wait until (and if) it reaches the level that is up to my standards.
Fact that FiiO has already released some version of Custom PEQ should be encouraging for those who cares nonetheless, perfect or not, it's perfectly usable, but yes, as with anything there is always room for improvement.
What is missing really, multiple custom profiles?
How about compiling the detailed list of things you want to see in the consecutive releases.
I am sure FiiO will look at them as they are as interested in improving their product as their loyal user base.