Not a bad idea...in fact, I voted for it... Hey, anyway, votes are not limited ;) But I think that the unlimited number of votes is part of the problem you want to solve. See https://feedback.canny.io/feature-requests/p/limit-the-number-of-votes-someone-gets.

I'll explain myself. The idea of a poll is good, the only thing that always feels strange about that is the fact that Canny (and equivalents) are voting feature that are supposed to help us prioritize suggestions, but then we feel the need to call for a vote on the next features to develop... Doesn't it feel strange? We vote to prioritize, but then we feel the need to vote again...

I think one of the reasons that explain that old posts tend to have more votes than recent posts is that voting is not limited. Due to this, votes are rarely removed by a user, even if the idea is no more relevant to him. With limited votes (which is not available at the moment), the long-time user that is interested by a new idea but who has already commited all its votes will have to balance the new idea with its currently commited votes. If he really wants to prioritize the new idea, he will have to sacrifice a maybe old but not that important vote. That helps keeping the house clean and diminish the need to organize a poll, as the votes become a living and more up-to-date poll.