Well... Avex and Toei are corporations, all they want is money. The are not companies that are going to hide their main sell window.
Am I the only one who thinks that keeping this hidden is wierd? Avex never did this before, NEVER, EVER. Why that? Because they sell things using the hype factor like "OMG!! Gackt is gonna sing the new Kamen Rider Decade Opening, go buy the single when it comes out". No! This year we didn't have any information during the Press Conference. As a matter of fact, the song that was playing during the trailer didn't look too much as an instrumental for a possible vocal song (The Press trailers for OOO and W featured an instrumental of their Openings).
The fact that we are two weeks away from the show's airing, and we don't have any CLUE of the opening singer, doesn't make you think that there is actually no singer? If Fourze is really trying to approach this "American show" vibe, why not do like the modern cartoons and shows from here and put only a instrumental opening?