This looks really cool!
What's the "up/down" key in the bottom row, centre, between the 2 return/enter keys? (I ask because my "dream" keyboard would have a thumbwheel just below/between the 2 spaces bars on an Alice layout keyboard) EDIT: it's a toggle key.
The different heights and layout look interesting; did you perform any statistical examination of which symbol keys were most used? Are you intending on using QMK layers to enter the extra symbols?
Can your fingers accurately hit all those modifier keys? Does that layout lead to less or more pinky usage? (I'm terrible at hitting other keys, I'm just a clumsy person)