Dual citizenship matter is much more complicated than just the ease of travel. In form of NRN card, NRNs are already getting the most facilities of dual citizenship except they don't get to carry a nepali passport, hold a govt position and vote in Nepal. What extra perks do they want to include with dual citizenship?  Does someone want to be a senator in US and Secretary of some ministry of Nepal at once? In my opinion, I owe allegiance to one nation at one time. Once you get a new citizenship, you have made your intent clear that you want to be loyal to your new country and not your old. To me, citizenship of a country is more about responsibility than right.