The more complete 'Poor you'

In sentences like "Go home," the 'You' is implied, as in 'You go home.'

What would be the implied words/full form of the sentence "Poor you"?

It certainly isn't "You are poor."

** I am editing this question to clarify what I'm looking for - I know what the meaning of this sentence is (both meanings and the difference). I'm merely curious as to how to write it out with the verb so as to make it a grammatically complete sentence. Just like 'Go' would be 'You go.' **

I'd guess it's implicating something like:

(I pity the) poor you!

The "poor you" seems to be used like an object here.

"Poor you" is grammatically complete. Despite what you learned in elementary school, there is no minimum standard for syntactical completeness. Really.

Here's an analogous construction:

I went and stuck a fishhook through my thumb. Stupid me.

Here, were you to render the second sentence as "I am stupid" it would take on a somewhat different meaning. "Stupid me" is calling yourself stupid. "Poor you" is calling someone poor (often sarcastically).

"Poor you" may be construed as an ejaculation of sorts:

ejaculation [ɪˌdʒækjʊˈleɪʃən] n 1. an abrupt emphatic utterance or exclamation

Under suggestion I'm posting this comment as an answer. I'd like to add that I ignore the etymology of the expression "poor you" or the variant "poor thing" and so on. I searched them but couldn't find anything up to now.

About what you wrote in your edit in your question: "go" as in a command, or imperative is a complete sentence. And it's a grammatically complete sentence.

Furthermore, "go" and "you go" are two different tenses, (in this case) the former being the imperative and the latter being the present tense. If you're asking about the etymology, that's another thing, but hinting that "go" is not grammatically complete is not correct.