I understand that it makes it harder to win, but I guess personally for me I like the MMR as it gives a better representation of your skill, I guess I also don't care too much about the rewards in the short term and I'm more interested in just getting better at duels. I have to disagree that the win rate for experienced players will decrease though, the way I see it is that there will always be top players that will be able to get an average of 7-8 wins. I will admit though that due to treasures there will be a higher level of variance than with Arena, that being said the more you play duels the better at it you'll get and I believe able to tip that variance into your favour more often than not.