If you believe that the difficulty in manufacturing a retina iPad plays a role in maximizing resell value, it will be at least as difficult to manufacture a mini with retina. Most here seem to believe that it will have to be the same retina screen used now (exact same resolution) packed into the smaller physical space. If it is hard to make the current one, it will be at least as hard to make the mini's version. If the current one is prone to defects and issues related to being retina, the mini version will likely be just as prone.
Some believe that a mini with retina will probably have to get a little fatter & heavier too... or that the battery life will be traded off somewhat to keep physical variables the same.
I've purchased a mini and have good faith that it will sell at a great price when I'm ready to sell. I just recently sold an
TV (first generation) for $90 (paid $229 in 2007). Per that rental concept shared above, I rented it for about $2.48 per month over the time I owned it (but I got to enjoy it for all those years while the guy who bought it from me didn't have those benefits until 2012). You might say, I didn't wait and he did. I took the hit in depreciation but got the benefits of having one of those for all that time. He got a relative bargain but didn't have those benefits for all that time.
If you want a mini, get it. Life is short. Waiting for the "latest & greatest" is a forever waiting game (as "2"s arrival will be followed by "Should I wait for Mini 3?"). If you have to chase upgrades, sell it on mature rumors before the rest of the world knows the new one is coming.