Ivern will inherently be better on the blue side of the map. He can share red buff with his adc and blue buff with his mid laner with no problem. However, Ivern on the red side will not be able to do this. Because top laners can't normally make use of red buff as well as adcs can, I believe that there will be a big win rate discrepency between red and blue side Ivern, and I'm not sure there's anything that can be done to rectify the issue. The champ's broken before it even comes out.
Also. Caitlyn is sort of the same way - Red side Cait can hide traps next to blue side tower - she puts them in a place that takes advantage of camera angle to make it impossible to see. A Caitlyn on red side can't take advantage of the hidden traps. I have no knowledge about whether or not the winrates for the two are significantly different (even half a percent), but it's the same concept.
Edit: Even if you don't agree with me that bot lane can best use it, it doesn't really matter. If top can use it significantly better than bot, the point still stands except that the opposite Ivern is better.
Also. How do I get so many upvotes with all my comments saying I'm not right? xD