So with a small sampling of voting, it appears White edged out Black, and Green got a single vote.
Hmm. I was hoping for at least a few more votes, considering how many folks viewed the thread.
Oh well. I promised to give some details on my little exercise.
Based on my exercise, the base power level for each color, based on round robin testing using mono colored decks that represented standard color based strengths.
1. White
2. Green
3. Red
4. Black
5. Blue
Blue did not get a very fair shake, as it could not be played correctly by the AI/robot. That being said, the deck could win against any of the other colors as long as its control factors could contain the other deck. The problem with this, as is always the problem with Blue control decks, is that if they can out race Blue's ability to control the game, then the Blue deck loses.
Green, Red, and Black all worked very well, and were quite consistent. Black ended up behind the other two because both Red and Green, curved a bit faster to finish off the Black deck before Black could just
overwhelm the battlefield.
Red could beat Green fairly consistently, unless the Green ramp got themselves a bit ahead. Green can go wide or can go over for the win, in Dominaria, and if the Red deck lets Green get a little too wide, or let the game go a little to long, Green stomps Red.
White has enough strong removal, and strong individual creatures that with a little bit of enhancement and well timed removal, could handle ANY of the other decks and quite consistently.
White barely squeaked out the top spot in this round of testing. Green would have taken the top spot, but it lost one more game than White, to the Red deck.
This is NOT a scientific study. Just a fun exercise on my part, to get a general idea on how the colors flow in the new set. I think the most expensive deck I built was like $20.
It was fun, and educational.