Dunno what you mean. It's just as Aizen said. He was disappointed, because he couldn't sense any spiritual pressure at that time. He assumed that Ichigo got weaker by doing whatever he did, which if you think about it is kinda silly, since he's ignoring the fact that Ichigo came there with Isshin on his back, looking different with his sword being fused on his hand. I'd also be curious if someone had zero spiritual pressure when he was a guy with one of the greatest reiatsu before that. On top of that Ichigo didn't look frightened at all. There's no way Ichigo would get weaker by trading his 150ish episodes emo eyes for his new "I'm an all confident badass" pair anyway. Don't know why Gin could see that when Aizen couldn't. I guess Aizen just never watched a shonen. Too busy producing power marbles and bullying weaker opponents.

I also noticed something else. Compared to One Piece's 5-10 minutes long Buggy inanities, Bleach did that way better in this episode with that Kuromadani scene. I hate when shit like that goes on forever in the most inappropriate situations. But it's fine when it's only short scenes.