Would be excellent to add an EQ on headphone output to compensate for various headphones.
Hmm. How would you know if you needed to tweak your preset or your headphone EQ? What purpose would this serve versus just tweaking your preset? Do you plan to use multiple sets of headphones that all sound different enough to need individual EQs? And then how would you know how your preset was supposed to sound?
The more I think about this, the less practical I think it would be. I’m not trying to be a hater, I’m just not seeing how this would be very practical or useful to a wide audience. I can imagine the support calls and forum posts where the person can’t get their preset sounding right only to realize they accidentally had the headphone para EQ set wonky.