You would need the verb to be in the imperative (I can't remember the correct ending, they're generally the future). This isn't, it's in the second person plural present and so in English you need the pronoun to make a proper sentence.
We have not yet seen others tenses, but I guess a more logical sentence would have been : "Milites, bene pugnabatis" = "Soldiers, you fought well". Unless it is a stimulus in the middle of the battle...
Sorry, I misunderstood your question. Yes, I was wondering about that too; if there is ambiguity, are we expected to use that tile? And where in the sentence? Probably right after the word that is plural as in the dictionary?
You've restructured the sentence. The Latin sentence has "milites" in a separate direct address, and the subject is just "you," rather than "you soldiers." Your sentence would be "Vos milites bene pugnatis."