If you only seek praise:
Great scene and nice layout. The colors are far too saturated to start off with, especially the blue and green.

If you only seek real input:
The biggest problems lie in the palace. The palace itself is well designed but has some issues for me, most notably scale. The rails are as high as the doors so they are not working. This also applies to the side stairs that 3 stories high. I would have a landing on the second floor to break that area, allowing for a roof over the garage entrance which now seems too commercial/industrial for a neo-classical building. The helipad is not a bad idea but a domed stained glass or just plain glass would be better because it would break the box AND allow one to see inside just enough to add dimension. Other areas have some minor scale issues so keep that in check its the single greatest error in isometric pixelart.

I would perhaps as you work on it make the glass one ramp of color maybe even not blue at all. Grey, lavendar or even green. The pool is fine this shade, toned down some. The pools in the garden can be mossy green/blue.

I see no more than 32 colors on this no matter where you go. Keep going :)