I will upgrade when they put the retina display in the Mini. I have an iPad 3 and the screen of the Mini doesn't really matter because I have something else when I need it.
I have said this on other threads and don't want to sound like a broken record, but...
For those that think an iPad Mini with retina isn't going to be announced this quarter, what will Apple release? I just think they need to release something in the first half of the year to keep shareholders happy and because that is what they do. Think about what they can release that is portable, the right price and will get people in line. I think the only other product that comes close to this is the MacBook Air. Do you think people will wait in line for one of those? The current Apple TV isn't enough of a draw (even though I love all four of mine), a regular-sized TV will not be cheap enough or small enough to create that store buzz, the MacBooks were recently (for them) updated, the MacPro is too expensive and the iMac was recently updated. For me, that leaves the iPhone, iPad or something totally new.
Concerning price when an iPad Mini with retina comes out, I think it will be around $50-$70 cheaper than the regular iPad with retina. I also think they will keep a non-retina Mini around like they do with the iPad 2. I feel this way because I read something from Cook or Ive where they said that they don't think of the Mini as a product that is lesser than the iPad. They said they just think of it as a miniaturized iPad. Looking at how things are priced now I could see the Mini with retina starting at $429.
I do think we could see a redesigned iPad similar to the design of the Mini. I think that will piss a lot of people off because it will require all new smart covers and cases - it would be physically smaller. Could that make way for an iPad Maxi with an A4-sized screen?