These may seem stupid because the answer may seem to make Decade overpowered
The Armor of Decade looks kinda bad, BUT if you think about it, with his powers, it makes kinda sense. the bulky part may not stay on for long, WHY? four words: CAST OFF CLOCK UP.
what I read, Dcd can gain the powers of the previous riders through cards, Right?
sooooooooo the Kabuto card, I hear it would grant Decade top speed, so Decade may have a cast off abilitym I say this cause if you look at Decade, like at the legs, the armor seems that it could come off like in Cast off, and then use a second Kabuto card would causehim to go into Clockup mode. just a thought.
and the wierd looking Gun/Sword/Card case is also explainable, I believe when decade puts a card into the case he could gain more of a skille...
Ex: Use kiva card and change the case to sword form, and he could gain the wild skills of Kiva in Garuru Saber.
These are just my thoughts