Well I don't really know why this change was made but by the looks of it, it targets on nerfing the dps classes a bit. I don't like being evaded more either (as a Fury) but I can see the logic behind it, when I can 1-shoot a ranger. This said, I'm against critical stike being raised - 50% seems high enough already.
On the other hand, this will indeed make boss fights even harder (some of them are rediculously hard already anyway). I'd go for the suggestion to lower bosses HP a bit to balance the difference.