I was optimistic update 2.5 would address this, but there are still issues with turret rotation and aiming while using the iPad Pro. 2.5 might have improved it some...I'm not certain, as I haven't used the iPad Pro for a while, and just finally got to test it again for a couple dozen battles.
The main issue seems to be the difficulty manually aiming while in sniper mode. I use this a lot, and it's nearly impossible to get off a snapshot while using the iPad Pro. Even when not trying to snapshot, it takes approximately 2-3x longer to aim with the iPad Pro. One basically needs to aim in the general vicinity of the target outside of sniper mode, then zoom in for fine adjustments. On the iPad Air (first gen), this is not necessary, as I can very quickly aim at a target, even in sniper mode.
It seems the "gain" or amount of movement a finger swipe generates needs to be amplified by a factor of about 4 to make the aiming performance on the iPad Pro equivalent to the performance on the iPad Air.
To play competitively with the iPad Pro, I'm finding I either need to play nothing but TD's, or drop down to tiers where players are less likely to be very skilled.