Read the link, that 5.8% vs 3.3% were for the exact same 110 polls. Apples for apples. Silver is not a pollster, he is a statistician - stop conflating things. He aggregates the polls. Rasmussen is constantly Republican biased when compared to the aggregate this year, so they have not shown any improvement since last cycle. Gallop has the same problem, but they are falling in line now - they don't want to be cause with bogus numbers when the election hits.
I would dispute that Gallup has been right-leaning.. they've just been more erratic. They had Obama +7 or something in September when others were more 2-4
