Personally, I am dumbfounded as to why this forum is so confused (I also find it strange this forum cares with so much emotion) why people buy one vs. the other. When the mini came out there were myriad posts (and threads) from people who were certain that the whole reason behind the mini's success was lower price (obviously it was techies and armchair IT profs playing marketeers), despite the fact that post after post declared the reason they *actually* bought the mini was the *size*. Funny that - a smaller device is bought because it's smaller, who'da thunk?!
Why does this forum have such a problem understanding that size matters, and it's not price that dictates people's buying choices, especially when it comes to Apple (a premium brand)??
I love my mini, it's a wonderful, wonderful device. I used to own a full sized iPad, which was also a wonderful device. For my needs, the mini is the one that fits best, and I base that on having owned both. Even when (not if) the full sized iPad gets the "mini treatment," I'll still opt for the mini, and I'd still do so if the mini were the same price as the full sized iPad.
The 5 I believe will remain different to the mini in size (the obvious), plus they'll offer more storage (e.g. 128GB will only be offered in the full sized iPad this autumn, a small premium feature), beyond that, I can't imagine too many big feature differences between the two.
I think a better question than where does the 5 go, is, "what happens to the mini when the market prefers smaller tablets (ignoring price differences)?" I believe Apple is smart, and if the market moves toward the smaller tablets, the mini is the tablet that will become the priority and focus of their main attention.