I personally think Go Nagai's works should be released in the US.
Not because they're any good, mind you. I want people to see how BAD they are.
No, but seriously... I think Mitsuteru Yokoyama's (creator of "Gigantor", "Giant Robo" and "Sally the Witch") manga (like his epic Romance of the Three Kingdoms manga) should be released in the US. Yokoyama was almost as important, versatile, and groundbreaking as Tezuka himself. His aforementioned Romance of the Three Kingdoms manga (his life's work of sorts) spans 60 tankobon.
I'm also very interested in the work of Nekojiru ("Cat Soup"), Koo Kojima ("Sennin Buraku"), Machiko Hasegawa ("Sazae-san"), Shigeru Mizuki ("GeGeGe no Kitaro"), Keiji Nakazawa ("Barefoot Gen"), and countless others.
Also, there are certain manga I'd like to see released uncut in the US (like Crayon Shin-chan). I am sick and tired of anime and manga being dumbed-down for American audiences.
I could name a million manga I'd like to see released in the US. How about you? ^_^