Thanks for the great idea, Miblo.
I've now implemented a preliminary version of this here.
You can create a poll with:
!poll+ some question? option one | option 2 | another option | etc
Close a poll with:
(if id isn't given, it does the most recent poll for the channel)
List polls with:
And vote with:
where N corresponds to the option's index.
I haven't yet done saving the poll data, automatic expiry, private messaging or a webpage, though those can be added later down the line.