To discipline passion there means to restrain it, to harness it, and to put it to productive use.
out there means "out in the world" or "out there in the audience". It can be understood as a clause:
... for the Audens [who are] out there.
That is, for poets who are like Auden, and who may be reading these words.
The other meaning, "weird, strange, somewhat crazy, extreme" would not be found following the noun like that, without BE. That is, "out there" is used as a predicate about a subject and is spoken as if it had "scare-quotes" around it:
Her poetry is really "out there".
and very rarely as an adjective that appears before the noun:
We will be reading some of his really "out there" poetry this week. possible, but relatively rare
but never as an adjective following the noun like time immemorial:
His poetry "out there" is my favorite. NO, not when it means "strange, etc"
Best Answer
One sense of rotate is "to replace (a person, troops, etc.) by another or others, usually according to a schedule or plan." (dictionary.com)
The idea here is that troops need substantial amounts of time off after a certain amount of active duty, but there aren't any to replace the ones in question, so the original troops will need to stay on duty longer than expected.