It isn't that bad. maybe 1/5. But fix one thing. Make the heroes cost 1 lumber and make a trigger so everyone starts with 1 lumber.
You should add a shop or two with items. If you know how to make item recipes, (If you know how to do it) then you should do that too!
You should improve the description.
If it's going to be fun, then the map needs heroes with custom skills. If you don't want to make custom abilities, then just take the ones that are for other heroes and mix the abilities. You should also change the abilities you use if they are the normal ones. You should add more waves!
And you have to do something that makes the map interesting.
I want you to update the map and make it better!
If you need help with anything, just ask!
EDIT: sorry, didn't see the shop, but you should make more items. Some damage items and permanent attribute items.