I love where it's going
But there are a few suggestions I have...
(Don't let the long explanation fool you, I do like it)
First, the very bottom of the base bugs me...I didnt know why untill I took it in photoshop and started playing around with it. You did a good job with your perspective in everything but the door. It just doesnt have that same top-down look; the whole door is shown while the top should be hidden a little. It's also cut into the stalk a bit. The way you did it, it needs work...only because it's off center (which is fine.) Make the left side of the dark color bigger than the right.
I respect you trying to use as few colors as possible, I really do, but the piece really needs a few more. Add one more color between each on the cap and stalk for a better round transition.
One last thing...
Lose the black outline. It makes it look so much nicer.