The 20% bigger than skyrim thing was only mentioned early when the game was announced, instead, they kept the "35 times bigger than TW2" thing much more prevalent as time passed, so maybe we should start making maths for that.
Anybody knows a pretty trustworthy estimate of the size of TW2? because what the slides say may be a mistake, but 20% bigger than skyrim sounds very very far away from what 35 times TW2 would be.
If the world of TW3 is both, 20% BTS( 46km2 aprox.) and 35 TTW2, that would make the world of the witcher 2 just 1.3 km2, which sounds extremely small and inaccurate, so on one hand, the skyrim comparison makes the game much smaller than the numbers we get from the slides, or the neogaf poster, or dualshockers, but the TW2 comparison makes the game to be closer to the big unconfirmed numbers, so which one is it?