I've always liked the idea of an evil cyborg leading the B.A.T. Legions... And it's really cool that he's that mass-murdering S.A.W.-Viper from the original MArvel book... I like that they used his secondary color scheme as well... It just looks better.

Take a look:

http://forums.yojoe.com/showthread.php?t=9928

I my self dons't really like the idea off the former Saw viper as Overkill, i don't think it's grovey it's more, nah, i don't like him.