We don't want to take the word 'out' totally out of the English language! We need it when taking out the trash and holding out for a bigger raise, and yeah, even when Harry is looking out over the lake. :) We just don't need it in terms of describing how something was said.

Also, 'shouted out' is not the same as the term 'shout out', at least not in my mind. 'Shout out' is a greeting, whereas 'shouted out' is an action, which again, should not be used as a way to describe vocalization. That'd be like saying 'hello' is the same as 'helloed' (is that even a word?). *g*

So yeah, I'm thinking that 'shouted out' would not work no matter how it's used as a dialogue tool.