Anime and Manga popularity wise in the US are a little
like poetry. Both will always have very strong cult followings and an
occasional showing of mass
interest but neither will ever be really popular and/or accepted by mainstream
America. Different series will not be popular for different reasons.

                  1. Ranma will not be popular not because there are too many
martial arts cliches that are parodied. Also I beilieve that people will think
that Shampoo is
a racist interpatation of Chinese people because of her accent (the way she
refers to herself in the third person all the time "Ranma date Shampoo.")

                  There are several other problems that are present in all
anime. The biggest problem for most Anime will be sexism. I believe that most
Americans will find the more popular anime series sexist. Ranma, Tenchi, UY
(to a less extent.), Evangelion, Oh my Goddess and many other series can
easily be labled as sexist in America and if any TV station that shows them
(with the expection of the Sci-Fi channel) will get a flood of petitions from
various political groups both liberal and conservative for showing the Anime.
Conservative groups will protest anime because it shows non-nuclear family
structures (Mermelade Boy and 3x3 Eyes.) Ms. Magazine (a very good feminst mag
for women in their teens through 30s.) will attack anime for sexist portrayls
of women (Ranma, Tenchi, Dirty Pair, et al.) The only manga/anime with any
real chance of becoming popular in America is Maison Ikkoku because it is
basically a traditional Romantic Comedy/Bizzare Love Triangle story. All you
need to do is update the time so it takes place in the 90s not the 80s.