I don't like that, personally. I don't see the Erlking as Autumn. He's the hunter. Nothing more, nothing less. he has no opponents but his prey, and they can't harm him...
Just my opinion. I like the smaller lesser court idea. That you and many don't is awesome, we'll likely never game together. If we do, you'll have to deal with it then, for now. I accept your position.
I will say that him beign a hunter and nothing more/nothing less makes him a little one sided, too black and white and in turn...boring.
As for his prey not being able to hurt him.... I call Bull$h1t. Per system, theres a few things that can hurt anything.
#1 any item or creature with the power: all are equal under god.
#2 soulfire
#3 any other plot device power or supernatural heavyweight
#4 any PC with a comparable refresh toa supernatural heavyweight, after all teh Dresden Files is all about exceptions and rarities or the novels would be boring. There is no reason the main characters of a chronicle should be any different.