"Sanmon Gossip" makes more sense because it's, as Frecklegirl has already pointed out, a "two kanji + katakana" title like her first two. So it makes sense that'd be the official title as it's her solo album, a "comeback" as they're presenting it (which was the case with HF as well and now you get a statement like "OK guys THIS time it's the real comeback" but whatever)
Was the "Superficial Gossip" title anywhere else aside from CDJapan?
That, and expecting a certain quality of the material from the title is a bit much - just wait and see, the wait's not going to be long
