[barnstenchfartface]

Also, as far as the making sense goes...Takumi being an Orphnoch is something they were hinting at throughout the entire show. The belts were always meant to be used by Orphnochs for Orphnochs, and throughout the many users of the Faiz Gear, the clear distinction between the characters that could transform and those that could not is whether they were Orphnoch or not. Kusaka is an exception, but he was always a unique case.

Other than that, I think MaskedRiderAsakura has it right. Takumi is seen throughout the show as someone who has absolutely no confidence in himself or his strength of character. He's scared of what he is, and says as much when he's discussing his past with Kiba. Specifically he addresses how the last time he transformed into an Orphnoch he blacked out, and has no idea what he may have done (the incident at the reunion, which we later learn wasn't him doing anything bad but nobody really knew). He fought as Faiz in order to deny that part of himself.

Personally I thought it was a well-done twist, but that's just me.