I feel this one will be more shock than Gaim's one because Shinnosuke is force to kill his partner, Mr. Belt so that terrible future won't happen.

Dark Drive's identity is currently unknown.

Or

We don't know of who will married Shinnosuke and become Eiji's mother. Maybe Kiriko, giving their interaction with each other. Possibly

Jam was the final boss in Gaim ;)

And W's movie introduced Joker and NEVERs, both related to the ending of the show.

Fourze had Rocket States in an episode or two. In the Surprise Future trailer, tbere was that Protodrive themed Tridoron. Is it hinting ast Chase transforming into Protodrive once more. It would be cool to see all three Drives together.