I haven't been in the place but will make it a point to go next year. The upper areas you are talking about... it would be good to see first hand what the steepness is of the seating. I have been in some upper arena areas that made me afraid to lose a step, which translated into pretty good sight lines.
If neither upper end can see the ice that blows, and I would think that would also suck for Bball.
I think with the way it's set up you get most or all ice in the existing seats, with some areas heads in the way upstairs, some perfectly clear......but just doing the outline in my head, moving the rink center kills a TON of seats. The steep pitch if the upper section I heard from, second hand, and it seems it might be dangerous for the elderly or drunken Ranger fans getting their arses kicked.
And for hockey or basketball, if you are near the top, the bottom part of the ice/court is obstructed if someone is leaning forward.
Sadly the view from MSG is way better.
I sat in the 200's section it was extremely steep and our view was definitely obstructed when people leaned forward...I can't imagine that would be the case for basketball however since the court is much shorter.