Cliegg Lars is definitely one of the standouts. In terms of the importance of the character to the plot and the sheer amount of dialogue he has, Cliegg is a solid candidate for a figure.
Aside from that? I think more arena Jedi would be reasonable choices. And I'd personally like to see some more characters from the Outlander nightclub. But I think AOTC is pretty low on the priority list for Hasbro these days.
The separatists are dull, they've knocked out damn near every Jedi human I can think of now... That one guy that tosses a saber to Kenobi/Ani is still noticeably absent I guess.
Actually, the two Jedi who toss the lightsabers in the Arena battle have been done. Nicannas Tassu was done in the Target exclusive Arena 2-packs. And Sephjet Josall was done in the TRU exclusive Arena multipacks.