rnnpmaybe,
I say go for it, and I don't think dropping out after 1 semester of the NP program would be the same to me as somebody quitting a master's or law school halfway through. I think your rationale (as you've explained it above) is O.K., you just have to be sure that when you explain it to the adcom, you don't sound like you are trashing your RN degree, or NP's. As a board certified internist, I actually agree with a lot of what you are saying about the NP movement. I actually don't have a problem with NP's per se, and I think there are a lot of things they can do well (health promotion/prevention, diabetic patient education, well woman care/gyn exams in healthy patients, etc.). However, I have concerns about them trying to practice primary care, at least without available supervision/help, just because the training is not really in depth enough to be able to reliably diagnose some of the complicated stuff they are going to come across. At least that is my opinion. Diagnosing patients and treating them is not easy - there's a reason med school + a residency was traditionally required to do that. It's HARD.
This is just an idea, but could you ask for a 1 year "leave of absence" from your NP program? That would give you the option of going back if for some reason you changed your mind in 6 months or something. You could just tell the nursing school that you aren't sure if the NP is for you at this point, and you just want to go work for a while. I wouldn't tell them that you're going to go take premed courses. If I were you, that is what I'd do, then I'd go work part time as an RN and start taking the required premed courses, say a couple per semester, and just go for it. Don't mess up your GPA because the one you have is good.