Definitely not-Kuuga. He wasn't just the most useless part of Decade but he was also one of the most annoying parts.

Man, he's so useless I forgot he existed. :lol

Actually, he does have one use.
He makes one hell of a flail! :lol

oh almost forgot about the two other movie riders that weren't Caucusus...could have been just Kickhopper and Punch Hopper in the movie...even if just using the Zechters

kabuto was useless, wat would we have lost, kagami would be the star... oh wait he is the star.

Yeah, I mean, nothing would be lost if Kabuto was removed.
Except for, you know, Kagami.

I get that you don't like Kabuto. But don't become a raving idiot over it.

how would kagami be lost, if tendou didnt exist stupid plots like hiyori falling for her own brother would be lost. then leaning toward and honest to god relationship between kagami and hiyori building up over time. plus the fact that he can sense the worm is just stupid

Tendou didn't steal the hyper zector, at that point Zect had rigged the hyper zector with a bomb.

Oh, and for useless Riders: Nadeshiko!