And technically, Sasuke's not in it. But they introduced some new characters recently, and one of them is played by Noriaki Sugiyama, who also voices Sasuke in Naruto and Ishida in Bleach. He really does seem to always play the same character... or at least similar characters, since I'm not qualified to judge what Sasuke's like. Only this time he gets to be a villain! Yay!
This of course brings me to our crazy theories about the casting of Ueki no Housoku. The casting director is Kazuhiko Inoue (Kakashi, Hatori, etc. etc.) and almost everyone in the series seems to be someone he worked with recently. Now I really do think that Inoue-san is a good casting director, who would not play favorites, but that doesn't take any of the fun out of coming up with crazy theories as to how the casting worked.
For example, we've mentioned our theories about Soichiro Hoshi being on a mission to abandon his cuteness. We like to think that him being cast as Sano, who uses a low voice with Kansai dialect and has a burn scar covering half his face, was an act of mercy by Inoue-san, helping Hoshi-san on his way to non-cuteness.
I was going to list some of our other theories, but really that's the only one. Although it is mysterious that Hoshi-san and Ishida-san are constantly paired together, like they were in HaruToki, which Inoue-san also acted in.