Been a while d00d, I was starting to wonder why I still come here
Anyway, Decade's finale didn't bug me, I think anyone expecting a self-contained ending while this series still has places to go was setting themselves up for disappointment. Anyway, I'd say everything after Hibiki World was just wasting time for Double to start with Complete Form being the only new merchandise to show off. I'm glad they didn't force it all into 31 episodes with so many possibilities left...
I like the characters in Double for the most part and the tactical form-switching is something the should have done ages ago, but maybe I'm too jaded from Decade because I can't really get into it... Although the Sonozaki Family stuff is really interesting.