Hey there! :3

Firstly, terrain. I like the ground area, but the cliff/hills area needs improving. I would add some more grass to the top of stone on some parts, like the base of the mountains.
A little more decoration on the terrain would be nicer too! Some more grass/flowers/wheat etc. I like what you have so far, but just a little more!

Secondly, organics. Good start with your trees, but there's some things that could be improved. Firstly, I think it would benefit you to add some branches to your trees - remember you have world edit, so you can use a brush to make the leaves! Make sure you use a high air percentage though.
The cows, however cute of an idea, need to be actual cow organics! It'd make the plot a lot nicer cx
The dragon I love! Some of the curves could stand to be improved, though, like the birch stairs in the wings. Same with the stomach.

Lastly, structure. I like the structures you have, you may need one or two more! I think a tower would be really nice somewhere on this plot :3 Maybe on the cliff/hill area.

Good luck!
- Dutty :3