The Hamlet Project

This is a very odd moment for Horatio to exclaim like this. He’s not really directly responding to what Hamlet just said; Hamlet was just talking about Rosencrantz and Guildenstern and only obliquely referred to Claudius, if at all, as one of the mighty opposites. (Maybe.)
So…this exclamation from a man who mostly just nods along and supports Hamlet – is very out of character and out of sync with the conversation.
Some have theorized that maybe Horatio means Hamlet but Hamlet is not King. He’s a Prince. And if it were about Hamlet, wouldn’t it be “What a King you’d be!”?
I could buy it as an exclamation of praise – the way a friend might call me a queen when I do something with authority.