Divert is kind of like extra Pierces. Divert doesn't do anything against planeswalkers, enchantments, or artifacts. It also doesn't stop spells that don't target...like Exhume, Natural Order, etc. It can be cute to Divert a Hymn to Tourach, or 2-for-1 someone with their own removal, but it might just be too narrow. Like, I would hate to have a Divert when I want a Pierce, but I wouldn't mind having a Pierce where Divert would have been better.