This piece passes on a lot of levels, but falls short on a big one - I call it the 'greyscale test.' Mentally (or literally, since it's a Photoshop work) put the piece into greyscale, and re-evaluate. The loss of the bright riot of colour immediately knocks the impact of the work way, way down: the only thing darker than about a middle grey is the lineart, and while that is beautifully executed, it ends up looking very busy, because there isn't anything else to visually anchor the image.

Pale pieces with a delicate colour range are always tough - it's immediately tempting to enforce the mood and the sense of delicacy by keeping the colours pastel / high-key, but that's exactly what you've done here, and so you see exactly why it's hard - there isn't a strong pattern of dark colour / shadows to weight the image or dictate the way our eye moves through it, so our eyes start following what darks there are - the lineart - and end up feeling very muddled and unfocused.

I don't have any issues with the composition, so my suggestion for improving the work would be to evaluate and revise your use of colour. I don't have a problem with the palette you've chosen - the various blues / greens / siennas work together in a harmonious way that creates a very specific feel, you just need more contrast. You don't have to put 'black' in a piece; if 75% of the work is smoky-pale, then dove-grey will seem very dark. Carefully evaluate the pattern of your darks - they do need a pattern, they're pretty random here. Assemble the colour with an eye towards reining in the motion of the lineart - it is intricate and beautiful, and I do not recommend simplifying it, but it does need some restraint / careful assembly of the values around it or it just becomes overwhelming.

It's a nice work as is; however it could be simply jaw-dropping with a little revision.