Stylization is fine too! Choosing simple shapes to convey something more complex is ok!
I like the original fat palmtree, it's very enjoyable. I have critique for making it more 3D but ... * n * I should just make an edit. Here's hoping I get time for it this lunch
The edit is made!

I suggest that you, in an earlier phase of coloring, decide how to color the topography so it corresponds to the lighting on a bigger scale. I here demonstrated it with icky smooth brush to emphasize the '3D render' feel of how the brain could work at this stage. It could have been better for me to demonstrate this with visible color clusters, actually, but I was lazy!
Using this kind of thinking I dicked around with your coloring. No cleanup done at all and much of the smooth feeling of your original palmtree is gone, but it gets my point across well!

I added 3 colors or something, so keep that in mind. This can definitely be done with a palette of the same size as your original, but lunch time is actually over and it's time for me to get back to work. So cheers!