"The boots are a symbol for something... what do you think?"
    I think the boots stand for something you want but don't need anymore - not necessarily due to death, but for other reasons as well. Kemmerich wanted to keep the boots if at all possible, but when he thought he had no hope of survival he said Müller could have them.

      "Why do you think the settings are not often described in detail? ..."
    Well, when the question is put to me in that form, the answer is clear, obvious, and irrefutable: Paul's immediate survival doesn't depend on what features of the landscape are half a mile away, but it does depend on how many cannon the enemy has.
    Furthermore, when I think about it like that, I can eliminate anything I imagine in the scene which would pose an immediate threat to Paul's survival. For example, he would have mentioned the fog: A fog between you and your enemies would make you unable to watch for any advancing infantry or siege weapons from the other side.