I would love to see a season two of Itazura na Kiss, Love In Tokyo (ie, something similar to They Kiss Again) or Skip! Beat. I absolutely adored TKA, and think that the J-drama would do it justice (since they pretty much hit it out of the ballpark with Love In Tokyo). Skip! Beat followed the Manga, and as such didn’t really have a satisfying ending (the Manga is currently ongoing). I think a second season where the leads were able to realize their attractions/Dun He Lian’s past can be revealed (what was up with the blond kid flashbacks?)
I would like to see a 2nd season of Faith and Hana Kimi (Taiwanese version). Faith because I loved the drama so much I just want to see more of what happens with the characters and their lives afterwards, and Hana Kimi because it was an awful cliff-hanger ending—I want to know what happens with Rui Xi and Quan!!!