I've been lurking on these boards for a long time, and the continual comments from non-iPad mini users about how the Plus phones make it obsolete just astound me. Those of us who actually use the mini find it to be an amazing form factor, perfect for taking with us anywhere (e.g., actually fitting in winter jacket pockets). As much as I am dying to get rid of my mini and upgrade the technology, the 9.7/10.5 inch iPads simply are not even close in terms of portability (fact is, I went to the mini originally because the weight of the mid-size iPad in my hands over longer periods of playing games or watching entertainment got to a point where it hurt). And, as others have said, while the iPhone plus screen is significantly larger than other iPhones, the screen is still significantly smaller than the mini's screen and provides a very different experience in surfing and watching videos and the like.
And, for all those who talk about how the sales of the mini have been terrible (other than around Christmas), maybe that's cause Apple has effectively left it for dead for years? Come out with a new mini and then let's see how the sales are. Better yet, just limit the mini to one-generation old Pro technology and I'd still be head over heels. (Charge a premium if need be to maintain margins!)