I've had a change of heart on the 36" a-arms, after a few trips west this season, and after getting some time on a 2018 Axys 155.
My current sled (it's for sale, if anyone is interested), a 2012 156 X3, with 36" arms, tips where you look. It's amazing in the deep. However, if you get on set up snow or hard pack, it becomes much more of a workout than a stock stance Pro. It wants to tip over on any side incline and requires a lot more effort to keep it upright, especially if you need to ride trails or tight trees to your destination.
I rode a 2016 Axys when they first came out and my '12 Pro was much more 'flickable'. I don't know if the Axys wasn't set up right or what, but it just didn't perform as well. Fast forward to a couple weeks ago, and I got on a stock 2018 Axys. It felt sooo much lighter and tipped on edge just as easy as my pro. Maybe it was better set up than the '16 or maybe they made improvements?? I don't know. All I know is that it's time to upgrade.
The wider stance of the Axys didn't hinder my riding at all and I think the 39" stance is probably the best for the vast majority of riders, when it comes to an Axys. For a Pro-Ride chassis, the 36" is the bomb in the deep.