No, I think the mini needs to be a little bit more midi, and gain an inch or two to put a cheaper but bigger 3.5" HD and a PCIe slot or 2. And also make the chip upgradeable. Finally with Santa Rosa, it can have 4GB RAM, the 802.11n Wifi and the Turbo Robson thingy all as optional extras. Oh an needless to say, big graphics cards (a GeForce 8800 GTX anyone) as an after-market add on as well as an optional extra would be cool too..
I think the real problem here is Apple's pride: there isn't a snowball's chance in hell Steve would let Apple make a Mac fatter than it is now. So they'll just do it the Apple way. Discontinue the mini and make a new Mac.
I certainly agree that all the changes you'd like to see won't happen on the Mini/Mini-type platform. I would love to see a 3.5 inch hard drive, 802.11n, and a processor bump up to C2D. Unless they go for a much more midrange computer, I see the next update/redesign having specs like that (except maybe not the 3.5 inch HD) and like what Evangelion mentioned.