Regarding your chances question, please see http://engage.wharton.upenn.edu/MBA/forums/p/3282/9399.aspx#9399.
I think the biggest obstacle for you, right now, is identifying clearly for yourself and for the Admissions Committee why you need a Wharton MBA, now. It seems to me that, if you are asking what doors would be opened via an MBA/MA, you haven't taken the first, critical step of doing your due diligence and research. If you are also asking others to tell you what benefit an MBA or MA will offer, you aren't ready to apply. You need to figure this out for yourself and have a picture/story of your career goals and trajectories (and how a Wharton MBA fits in) before you apply. There are a near infinite number of doors that a Wharton/Lauder MBA/MA can open - it just depends on what you are seeking, and I do not see enough information in your post, above, to be able to assess whether or not an MBA/MA would best help you open the right doors.
As for the humanities question, there is nothing that is inherently wrong or right about a humanities background. The Wharton MBA program is well known for being one of the more analytically rigorous MBA programs in the world; as such, it tends to be more quantitatively/data-driven than other programs. If one has quantitative aptitude, though - and can clearly demonstrate this - there is no reason why you should not have a viable chance at admission.
Victor (a government major in college)