LOVE the new Banshee!
I actually have been waiting a while for Mages to get some defensive items. Like So tired of AD champs building Hexdrinker and becoming basically unkillable while also one shotting people, they also have access to steraks and Edge and now GA will be directly for them. I think Banshee's is a good way to give mages a bit of defenses and makes up for them losing Abyssal passive and GA as a viable item. Also banshee's passive was always pretty easy to pop before fights so it just makes mage positioning even more strick to make use of that passive in a teamfight. I really like it. We'll see how these tank changes tho effect Mages in the long run, I have a feeling Mages are going to come out really weak and need more compensation buffs with the direction tank items are going.