Hi - short term listener, first time caller....
I'd like to offer a few things to the thread, if it's not to late.
The way I see it, there are currently four options available: iPad 2 (older processor, lower resolution screen), iPad 3 (older processor, Retina display), iPad Mini (older processor, lower resolution screen, smaller form factor), and iPad 4 (newest processor, Retina display). This gives buyers a choice of the type of iPad experience they want at different prices.
I also see the possibility of a couple different outcomes for a new Mini:
1.) The same size, weight, and screen as the current Mini, but with an upgraded processor and/or memory and/or storage capability. There are certainly enough rumors floating around that support this theory. I would envision this Mini sold at the same price as the original Mini, with the original now being reduced in price (as was the iPad 2 when the 3 came out, and the 3 when the 4 came out, etc.).
2.) The same length and depth as the current Mini, but thicker than the original (as the iPad 4 was over the 3) to allow for a Retina display with an upgraded processor to run it, as well as a larger battery to maintain current battery life. I envision this new Mini being priced higher than the original (between the original and the iPad 4's current price), with the original maintaining it's current pricing.
With either outcome I would guess that the iPad 2 is no longer offered, and neither would the iPad 3 if an upgraded full-sized model is introduced. This would leave a low-end and high-end option available in both the full-sized and mini models.....maintaining four available options for the consumer.
What I also consider a possibility, and one that I've never heard mentioned before, is that a new Mini with Retina display being the only new iPad released this year. This still leaves four iPad options available, with both a low and high end option available in either size, with four different price points.
At any rate, I would welcome a Mini with Retina display. Whether or not the Mini is "significantly" more portable than the iPad 4 seems to be debatable, according to varying opinions. What I don't think is debatable is the usability of the Mini - it can be "one handed", allowing ease of use by children, those with small hands, lying in bed, etc. I've spent many hours going back and forth between the current Mini and the iPad 4 (I don't own either but I have been borrowing and/or spending too much time in local stores), and even WITHOUT comparing them I find the current Mini "fuzzy" when viewing web pages or anything with text, even though the text is large enough to read. Of course, this fuzziness is rectified with a fair amount of pinching and zooming, but I find it a much more pleasant experience to use the iPad 4 because there's way less zooming required (for me, at any rate). In my "tests", I've come to the conclusion that I won't have to do the majority of the zooming I do on a Mini if it had a Retina display.......so, I'm hoping that the new Mini has Retina, and has no more than a minimal increase in size, weight, or price!