It's not perfect, but it's not deeply flawed either; the biggest drawback is probably that it's only up for one day, but with 150 votes I'm not sure how big a factor that is. It would be better if weren't possible to vote once while logged out and again when logged in (perhaps Quick Poll voting should, like posting, require a login to ensure no one gets more than one vote). I doubt that's a huge factor though 'cos I can't imagine an attempt at mass Quick Poll rigging (conspiracy111 ). I'm not privy to all the site traffic stats, but unless a lot of unregistered non-members are voting 150 votes is about 25% of the people who've ever posted on the CMB. That includes wotmaniacs who left in the first weeks, those who've left since, newbs who didn't stay, and the odd half dozen snoops. If there's site traffic showing that many registered users logging in on any average day maybe those 150 people aren't a representative sample, but I suspect that's not the case, though of course I can't be certain.

Ultimately, your premise boils down to whether you think WoT fans are disproportionately more likely than wotmaniacs and RAFOlk to vote in the Quick Poll, and my bet is the reverse is true. The logic holds either way: TODAY, WoT has a big footprint in the world of speculative fiction, and RAFO has uncommon access to resources for exploiting that current trend to its benefit. Down the road RAFO will need a primary focus that is NOT WoT, just as WoT sites will, but WoT offers what ought to be a welcome opportunity to develop the sustainable, uniquely RAFO (i.e. not former wotmania) community to reach that point in the road as well as progress beyond it. That the opportunity window will close in a year or two is reason to seize it while it still exists, not marginalize it as we watch it close.

EDIT: This question made me consider doing something Stephens question below convinced me to do: Use each MBs search page to get a count of how the total number of posters on each. Results are as follows, in descending order of unique posters:

WoTMB: 689
CMB: 624
BMB: 526
TV/FMB: 391
GMB: 217
RPMB: 54 (!)

Still not precise or a smoking gun, and it does indicate the Quick Poll underestimated participation in the BMB, but unless one MB is getting spammed a lot more than the others it's pretty clear the BMB is a distant third to the WoTMB and CMB in terms of popularity. Popularity doesn't necessarily correspond to merit (rarely, in fact) but it's very relevant to growth potential.