Is the question:
What team will Peyton Manning most likely got to?
I understand it may generate opinions, but if the answers are based on history and/or fact...
Well, it might be a really helpful, interesting question.
I think the question itself contains clues about it being a good question or not - things like "most likely" are not going to generate a fact-based answer, just speculation. My vote would probably be no, not really a good question for Sports.SE
There are reliable ways to determine the statistical liklihood of the various teams he could go to. You start with the set of all teams. You then cull out those that for, whatever reason, do not need a quarterback. You continue excluding teams until you are left with a couple. After that, you are left with speculation, but we should note that speculation is not discouraged on stack exchange: discussion is. If the speculation is rooted in observation and reason, I don't see why it wouldn't be allowed.
And since the question can be answered in an objective manner, I don't see why the question itself should be disallowed. If particular answers to the question are formed poorly, then those answers should be corrected. In my opinion, a question like this will require an extensive knowledge of the game, the state of the current teams, and the motivation of the management of the various teams. In other words, this question requires expert attention which is exactly the kind of thing we want.