There's potential in this topic, but I think there needs to be some clarification before it can proceed. I know you don't want to do comic books vs. graphic novels, and that's cool, but if you want to group them as one item you need to explain what they have in common. You may not be able to name it at the moment, but share with us what you plan on doing to find out.
I also felt your explanation of "others" is too vague. While the grass-skirted man is certainly a foreign characterization, I'm not convinced that he's a wildly-amalgamated character. I got "Yucatan Peninsula" from him. Furthermore, "others" could mean something ethnic or political or really anything deviating from the norm. This is to broad for you to really pursue fully.
Because your idea is, as you say, "rought", it also means that we don't know where you plan on pulling your research from. I would give the idea a rethinking and try to zero-in on something tangible and supportable.
I agree with your feelings of defensiveness when it comes to people who assume that just because the term 'comic books' has gotten a less than professional connotation over the years, that all forms of comics and graphic novels are juvenile and not to be taken seriously. I think you could create an interesting paper based upon proving stereotypes/myths about comics and graphic novels wrong through arguments and examples. It might be useful to you though to narrow the focus of your paper to very thoroughly addressing only two or three points about graphic novels as opposed to going through many arguments in several short paragraphs---I think it would give the paper more strength and focus. As for your alternative idea of writing on 'the other' in comics, I think it's viable but like I said about talking about the legitimacy of graphic novels, it would probably help to narrow your focus down a bit to a few specific characteristics or functions of the other that interests you. Overall I think both of your ideas are very workable.
I guess my job is to be a little more blunt: to what extent are your two topics arising out of desperation at the abstract due date? The most important thing is not to back yourself into a topic that you really don't have much of a stake in. Regarding the first topic, there's an essay to be writen about the emergence and mainstreaming of comics -- which is to say their new uptown moniker "graphic novels." In part, that's driven by publishers newly willing to collect individual issues into a single volume; in part, it's the emergence of authors self-consciously imagining freestanding "novels" instead of "story arcs" across issues of an ongoing series. Hilary Chute suggests substituting the term graphic narrative, which I'm tempted to use the next time I teach the course. So this topic would be somewhat about literary history or, as you parenthetically suggest, the creation of a new cultural figure who's sometimes respected and other times a figure of pity: Loser! Your second topic's not really related to the first. It's so broad I hesitate to say much in this forum. Really, my advice would be for you to drop by during office hours and chat for a while. You probably have a really good project that you're not yet recognizing, or don't realize you have permission to write....