Kanye's part is way too long. It feels more of like a collaboration (aka Good Time) instead of a feature remix. Plus, why would they release this when she's already #1 on iTunes and has the Hot 100 on lock? It's gonna kill her longevity.
The remix won't sell as much as the original track obviously.. Diamonds is already at number 1 on Itunes. So how should the remix sell more than it? Doesn't make any sense.