now m sure many people will say no but imo YES it is hard to customize. problem i faced with django is, if you go with defaults, it is pretty easy. but once you start customizing, you end up overriding lot of methods. so much DRY & magic. you can't code without api doc. for some people it may work but i don't like magic at all. i have seen lot of bad django code in production. people just copy paste from stack over flow without understanding and make requirement work.
And this is why amigo you should try Flask. Its simplicity will blow your mind.