Will Blockstream Core agree to shift to 2mb if bitcoinocracy poll indicates more coins are supporting 2mb ?
That's possible, however the poll is unlikely to indicate such.
I doubt this. Majority holders are probably not yet aware of this poll. If we make an effort and make them aware and win the poll, then Blockstream might back out again and say "bitcoin is not democracy", "mere winning wont do, you need 90%+" etc. So, there needs to be clear message from Blockstream that they'll move to 2mb if they lose this poll 51:49 and give us three months to send the message across.
I think bitcoinocracy poll is a quite good way to measure the economy majority interest, it can be quite handy for future change request evaluation, if the question is more human understandable
Many people vote blindly or based on rumor, so there should be first some small test for investor's knowledge level and then they will be directed to different poll that suits people with different understanding of bitcoin