I've had some talk with HT, and the impression I got was this beta was a quick, makeshift version to test the colors out.
For one thing, like you've pointed out the lack of contrast needs some addressing. And the little problems with tile transition has caused the terrain quality to be more poor than ever.
However, the brightness itself, is a step in the right direction. No matter how good it looked in the mock-up, a mock-up is a mock-up - the real results proved that it needs some more attention than just futzing with the colors, but I think overall, the new beta colors proved its point.
HT said that they're still working on it, and I have no doubt the end result will be much better.