Gallup's figures on party affiliation declines for both the Democrats and the Republicans are interesting.   Independents truly do appear to be the people selecting the President this year if Gallup is right

While your site attempts to account for the cell phone and the landline components,  I wonder if these polls are as accurate as they were 20 or 30 years ago considering the continued growth of cell phones.  I haven't had a landline in 16 years and my 40 and 35 year old kids have never had a landline, nor have most of their friends.  

As far as weighting the averages, my knowledge of statistics is too basic to go there.  Seems more like putting the butcher's thumb on  the scale to me than something I can rely on.