Gear Acquisition Syndrom (GAS) is insidious.
Unless you are restricted by a beer budget and a champagne diet, you will never be satisfied. After the D7100, comes the D800E. Then... hmmm..... "should I have gone with Canon?"
??? what about Sony, after all they lead on Sensor mfr, making them for Nikon....
Will the questions never stop? No, not if that is your mentality.
You already are dealing with the first element of GAS....The distaste for what you now have in your bag, even though you have very likely NOT run into it's limitations. It doesn't sound like you have even explored what "new" glass my do for you?
But the rationale there is, will spending money on new glass just lock me into a model limitation. You already know it will lock you into a MFR selection.
Do you walk by camera stores, with your checkbook and pen in hand. Do you wake up at night in fits and starts with visions of "better" camera's in your hand.
If you work on a building project, are you OK with a 2.25 HP Skil brand power saw, or do you spend the money for a 3.5 HP Makita. Is Black and Decker OK, or must you have a more exotic tool. Does the Makita make cleaner cuts than the Skil brand saw. Well that depends on the blade tooth size and quality of the blade steel, much like better lenses on the camera.
Is that how you think... better camera, better pictures... Yes and no.
But bottom line, it's already too late, and the questions you ask are fruitless. We can't help you if we don't know how you "rationalize" all the things you want in your life.
You are already clearly "DONE" with the 3200. That much is a given simply from your first post.
Buy the D7100 and sleep at night.... at least for a couple of weeks, because that's probably who you are. Tomorrow's camera will be better than the one in your bag today. Of that there is no doubt.
Furthermore, unless you are restricted by a beer budget, you won't miss the money you spend on camera gear, or power saws.....until Retirement!!!
How much did you contribute to retirement in this month's paycheck or income stream.
Boo...Hiss!!! (Hush the voice of reason)
And the last thing to ponder. The D7100 is already getting "long in the tooth". Isn't it due for replacement before the end of 2014??? Hmm?
And who can even guess at the marvelous advancements in the new models. Well, surely the rumor sites have something to offer in that regard... let's go take a peek at www.nikonrumors.com???