Actually, Nepal might well be important, at least to some degree. It's next door to India, is it not? And India has it's own problems with issues related to the caste system, and Naxalite terrorism. A Maoist victory in Nepal would no doubt destablize India, and by extension South Asia in general.
Yes, India is one of the brighter spots in the world, at least potentially, for the U.S. Our enemies of all stripes would love to interfere with our budding alliance.
In geopolitics, every country can matter, and Nepal being on India's border is enough in its own right to make the country significant.
You are probably right, to a degree. Maoist victory in Nepal would obviously have negative consequences across the region, and India will be one of the most important areas of transition in the upcoming century. I suspect that the relationship between India and Nepal is rather one-sided, however... I imagine the worst case scenario would make Nepal the Cuba to India's USA.