The Note 2 is a great device (or seems like it should be, considering).
However, I think the people who get it are banking on two things, first and foremost: (A) screen size (B) s-pen. The next Nexus probably will have a decent sized screen, but not the largest screen that can comfortably be your everyday device. And the s-pen is a HUGE selling point. the Note becomes such a different device having the stylus build in (much like the iPhone is a different device when Siri was built in to the phone, integrated with all areas not just web search).
There might be a small segment that crosses over, but those people are probably the ones that just one the newest and greatest, and probably change phones every 4 or 6 months anyway. I think the next Nexus is going to have to compete with regular flagship phones like the S3, the OneX, iPhone 5s or whatever other flagship gets dropped between now and then. It probably won't have to compete so much with "niche" devices.