-Butchered Yuusuke's character. I'm not even talking about henshin, he went from the "heart" of the group to a pointless and selfish comic relief character, who runs away from monsters, gets beaten up in one attack and is ready to leave Tsukasa's party and stay at any random world.
-Messed up the origin of the K-Touch. It's not related to Decade at all, so far, or even to any Riders. It's just a piece of equipment that randomly became his power up.
-Doesn't know how to write fighting scenes. The special characteristics of the Riders, like Dark Kabuto's clock up, have been completely ignored.
He's just randomly reusing suits by this point. An Undead suit was used as a stronger roach in Diend's world and the random Riders from multiple worlds as natives of the Nega World without any explanation.
-EVERY fighting scene with the Complete form's kamen rides so far has basically been a one hit kill too. It's much less interesting than the standard Kamen Rides.
-Managed to write two consecutive worlds using basically the same plot for both (monsters control Earth, although each one had a different spin, but, either way, that was just pointless).
Edit:
- Almost forgot. He spent almost half of the Nega World focusing on Natsumi... and yet managed to fail adding or showing anything new about her character.
A minor grip, that I haven't seen other people mentioning, is the lack of original enemy suits. I thought they were nice, and I've been missing them in these 4 episodes. There's already a new one with 2 forms in the Shinkenger World episodes... so I guess it wasn't a coincidence that only the Inoue penned episodes lacked these suits.
Haven't we been explaining why for the past 6 months?
Not really. There are several people like myself, that had been enjoying the show until these crappy Inoue written episodes.