I like it, this is a solid effort. I'm going to echo my general complaint about fighters, though: it needs some out-of-combat stuff to do.
Thanks. I've been trying to think of how to include utility abilities, and my first idea was to allow the Scion to gain a new ability every four levels or so that was solely meant for out-of-combat use, so as to avoid infringing on the Battle Arts. However, I'm still not certain what abilities they should have. Any ideas?