Some of the costumes however...
To me, Yuki doesn't have a clear image yet as a solo artist. Yes, she is a great idol, but what kind of solo artist will she be? Will she be like Otsuka Ai (wacky rock with emotional piano ballads) or like Matsuura Aya (idol choreography, etc) or something else entirely?
As much as I like Yuki, when you line her up against AKB48's top members she is a bit bland. Even the other girls make fun of it (AKBingo fashion episodes, etc), so I think it's something she (and the management) realize. She doesn't have the superstar aura someone like Goto Maki had when she was debuting solo.
With that in mind I think the outrageous costumes are to boost her stage presence a bit more; to truly give her that solo artist status when she is on stage. Even so, I think it's a mistake. Most of them look ridiculous and they distract rather than add to the experience of Yuki's performance.
Personally, I think she should just focus on slow paced songs. I mean, I understand why AKB48's hit singles and French Kiss songs are included, but if they truly want to set her up for a long term solo career then I feel she should play her strengths. The Kazenbai clip in the preview is leagues above anything else they showed. In other words, go for a Matsushita Nao (slow, piano, classy) image rather than the grown up eternal idol.