There aren't any numbers out at the moment but judging by what I could tell from the patch notes, MCH barely got much of a dps buff, just 60 potency on the 1-2-3 combo and 100 potency on heat blast spam, which, while isn't bad, isn't really much compared to the other job buffs I've seen.

I've seen 3-4% dps increase being used for the job but again, I don't know for sure, but IMO the job buffs don't really make it more viable because while yes it got buffed, so did everything else that isn't Monk or BLM