And then proceed to give new WW less base MS than old WW
As a general rule, you give a champion that synergizes well with a stat low base values for it because it's expected that they will buy more of that stat throughout the match. The idea is that it will reward the champion for building up their strengths without making the specialization overpowered. And by the same token you tend to give high base stats to champs that don't really have much incentive to buy from that stat, so they can forgo building upon it without being gimped by it.
That's why Jinx for instance has the lowest base attack speed in the game, because AS is so good on her that she'll probably get lots of it anyway. And Akali one of the highest because she doesn't have much incentive to buy AS items (AS is better on her nowadays though).