I'm about to update the Netty subsystem to make some changes after the feedback we got from the WildFly team [1].
I'm indenting to first address the concerns about the extra xml element, use a module attribute to point where the factory class is located, and then the threading tips. 

They also recommended that we create a specific subsystem for SimplePush. 
The advantage of this as I see it is that we would then have a schema for the configuration options for SimplePush (and also the SockJS configuration options). Without this we need to add a generic properties element to the Netty subsystem. 

Another advantage would also be just having one single module instead of two like we currently have (one for the Netty subsystem and one for SimplePush).

One disadvantage might be if we later would like the Unified Push Server to be base on Netty it would also have to have a specific subsystem.

I wanted to people think is the right approach here for us?

[1] https://community.jboss.org/thread/229635;cid=1374049762089-667