We've also been recording public room activity for a while, so that will be a huge factor in what public rooms to remove and replace. As far as those public rooms go, this poll will be something we use as a reference for what mods to replace them with, what room types to focus on, and building a strategy to maintain public room activity.
With the ranked rotation, it primarily depends on the results of this poll and the consequent discussions.
As you pointed out, the number of respondents, the number of valid responses, and some other number crunching to filter results will also determine the relevancy of the poll.