The iMac is not a desktop in the general sense. Is an all-in-one. It doesnt follow the same "guidelines" as a desktop computer. And when I say guidelines i mean "user expected" guidelines.
The 2012 iMac is the 2012 iMac. It is not a desktop (though it can sit on a desk).
If you like to have big files stored on your main computer like music and photos there is an iMac that meets your needs. It may not be the cheapest one though.
If I know that I need to haul 8 foot pieces of lumber, I don't go and buy the truck with the 6 foot bed then complain about not having the truck with the 8 foot bed. I buy the 8 foot bed.
Common sense.
Ah, don't worry, I'm tech savvy enough to see how iMac is different. I own a Mac Pro after all for certain reasons.
The thing is, iMac with it's current generation, stopped being a good value proposition, especially here in Europe with price going high.
Adding SSD as additional drive is popular on every computer, iMac included - and yes, it's mostly because of money (just look at Apple's SSD prices). The price of higher 21.5" iMac that has additional SATA port is the price of 27" base iMac that used to be before.
But enough of complaining, Apple has it's own reasons to do the things the way they do, I learned that in those few years using their computers. I just wanted to express disagreement on the decision to not have that port there. Base iMac used to be a computer that I would recommend to anyone who'd tell me Apple computers are expensive, not so anymore.