I think its hardly surprising in a place called NS-Europe that the area most clearly modeled after RL Europe is the most popular. Most people (probably) are here to RP European-esque states, and most of the Himyar and "Americas" area doesn't have much identity besides former colonies that grew up and still trade and are mostly interacting with Europe. Before anyone jumps on me obviously there are exceptions to this. I'm not sure theres any map-esque fix to that other than simply expanding Europe. Though reducing land locked states certainly couldn't hurt, and may yet prove beneficial. Maybe I am just being a negative nancy.
Another possibility might be an expanded "America's"/Columbia with true west and east coasts (as opposed to being mostly one nation thick) as opposed to the larger Himyar.
Another possibility might be an expanded "America's"/Columbia with true west and east coasts (as opposed to being mostly one nation thick) as opposed to the larger Himyar.