Well, I trust Capitol, but in my opinion it's too soon. They could have gone with Dark Horse for at least one more month, it's still groing on some radio formats including Urban.
I don't think one song will kill another, because Katy proved during the Teenage Dream era many times that she can have two hits at the same time. But, because Unconditionally died so quickly, I would wait more. This era is going so fast.
Great timing. However radio stations, knowing this is a single, will probably still add the song to their stations (much like by the add date, most country stations added Play It Again (and it was within the top 20 of country airplay by the add date time too )).
)).
