Kamen Rider Decade, period. Decade pretty much ruined the way Tokusatsu looks at things. I'm sick of the nostalgia, I'm sick of the desperation to tie everything together, and I'm sick of the fact that Tokusatsu is becoming the Buu Saga: Every new character is the most powerful ever, so watch all of your favorite characters look absolutely useless so these bland ones can be amazing in every single way. I blame Decade, which took a neat idea of using past Riders and formed it into a crutch. Then Ultraman decided to make their own Decade (Zero), and Sentai (Marvelous).
Edit: I know someone will try and argue this, but Stronger and Black RX did indeed give respect to the previous Riders, because though the new Rider was more powerful, they were still properly integrated without taking over or looking pathetic.