I have noticed that the horse no longer attacks. This may be intended to help balance the 2 follower option. I just wanted to bring it up as it was not mentioned in the patch notes. The horse does not attack either with another follower or alone.
Thank goodness, that was among one of the changes a lot of us were asking for! 
If I may add to this, I would say not only is the horse not attacking awesome BUT the devs need to lessen the aggro it attracts.
While I was waiting for my Berserker to be converted I took my trusty steed into battle and was disappointed in the amount of enemies focusing on him and not on me, while I was clobbering them with my axe being dismounted.
I understand there should be risk dismounting and losing your mount but I would say a 10% chance to be targeted or even less would be good. As @Jim1 pointed out in another post, there should be risk and I agree.
