I had a problem with the fights on Decade.
At first, after watching Den-O and Kiva, where the main Rider was always running around and attacking the opponent head on, it was a refreshing change of pace since Decade would keep his movements to the minimum, hell he didn't even have a fighting stance. The problem arouse when Diend was introduced, because he fought just like Decade, so the fights pretty much became who could dish out the most attacks or power-ups.
The worse part is that when Diend did actually fought dynamically, he looked awkward.