That's a terrible idea: anyone can vote on a poll, which makes (alt) abuse very easy.
In some others forums that I am active on and that are much older than bitcointalk they have the option to make poll voting public, so everyone can see who voted for who. Would something like that be possible to implement here as well, forum software wise?
It's technically possible to implement such thing. But the real question is whether theymos will implement such thing, especially when new forum software is in development (although no one knows when will it be ready)?