It's not a bad idea to use the new blocks, though in my opinion they're really.. ugly. Not relevant to your map at all, I blame whoever invented the blocks.
Regarding the map, remember to consider the gameplay as well as the aesthetics. I feel like the tower areas are not big enough, not symmetrical and therefore not pleasing to the eye.
I'd suggest possibly redesigning the path, so that the tower areas are balanced for both 3x3 and 5x5 towers to fit on.
Apart from this, the red and blue clay do not compliment the purple castles that you created. There's barely any block variation, making it look incredibly simple and monotone.
I'd suggest spicing up the design of the castle itself a little. Make it bigger, more interesting. Add depth. Depth is what you find in every successful map for pretty much everything.
Then add suttle red and blue accents around the castles to determine which side is who.
The chorus fruit... it's not a bad looking thing. It's just that there's too much of it in your map. Once again, making the map very boring and repetitive.
For this, I would suggest possibly adding a few improved end ships and mansions - bearing in mind not to use purple blocks only. Force the wow factor out of the map.
Adding to what
@Undead said with the dragon, make a lair! Make it interesting. Possibly create your own custom end caves with dragon eggs and little baby dragons surrounding the map -learning to fly! Whatever you wish.
Placing around a bunch of chorus plants and calling it a 'forest' isn't very creative now, is it? Even if it was a forest, they don't stop at trees (or chorus plants in this case).
You can find creatures in forests, caves, interesting architecture created by nature itself. If you need inspiration with your theme, look at photographs and other references - this will surely boost your creativity :)
Overall, the concept isn't bad at all. But that's just the concept. It must be developed, made to look interesting - with depth, ideas and fun interactive builds.
Good luck!
