The mortars and wizard towers are well-placed. But I generally advise against having such large sections of walls with so many buildings in them (aka, the large sections in each corner of this design). A large group of giants wizards/valks/etc would very quickly tear through them.
Personally, I'd advise having fewer, smaller sections that mainly contain defenses and storages. Place the non-essential buildings (like barracks, collectors/mines, builder huts, etc) outside of your walls. They will act as a buffer for the enemy, making it take longer for them to even get to your walls (and giving your defenses more time to destroy them). Also, having stuff like that outside of your walls makes it harder for an attacker to funnel troops into your base.