I'm extremely intrigued by this whole vote trading mechanic. It will no doubt require a bit of balancing, I can see the AI completely failing to use this correctly when first implemented. Fortunately Fire Axis is fairly reliable at fixing such problems (well, in my experience of bugs and inconsistencies anyway!).
I hadn't even considered how much Polynesia is going to benefit from their Wayfaring trait actually. On any sort of Continent-styled playthrough they would be able to meet all the Civs extremely easily compared to others. The only way I can see any other Civ being in competition is England with their 2+ naval movement, provided there is a coast-tile connection (Helcaraxe - Middle-Earth / Undying Lands sort of thing). Otherwise it's going to be the Inca who are always going to be the ones first getting the congress if it's a Pangea type map. Ignoring hill tile movement restrictions makes for huge mobility for all units, meaning traversing the map will be much easier.