Will E12 be able to use while charging? This is a big flaw for me for E11 personally and why I wouldn't concider one. Also how many bass boost settings are planned? Any chance to add more than the 2 on E11, especially at least one lower one. I don't know how E11 is configured but I'd personally opt for +1.5dB boost, 3dB boost and 5-6dB boost.
Personally, I think the two bass boost settings from the E11 plus one midbass reducing setting would be great, as bass boost can be very fun but many headphones and music genres could benefit from tighter bass control. Gaming too, to make explosions less disorienting
Then again, I'm not everyone. I've noticed other present and former violinists seem keen on tight, controlled bass in their music.