I welcome the thinner design. That's the progress of technology. Look at anything we take for granted that came out of the 20th century that has gotten smaller, faster, thinner, better:
Radios - FM tuners are incorporated into nearly anything these days, no longer is a radio a giant console/piece of furniture.
Televisions - TVs have gotten so incredible thin. Yes because we hang them on the wall, but even on a stand they're much more pleasing the thinner they get. No more tubes. Flat screens that are extremely thin. And theres still room to get thinner, lighter, and better.
Cell Phones - We aren't carrying around these monolith devices with giant antennas jutting out of them anymore. Look at the latest cell phones. They're thinner than a deck of cards and will continue to get thinner.
Laptop Computers - The original laptops were huge! Now they're amazingly thin. Look at the MacBook Air!
Desktop Computers - Sure the All In One has existed for quite a while, especially from Apple, however, as everything else, it keeps getting more powerful, thinner, and better, each and every generation.
This is even seen with modular PC parts! Mini ITX motherboards offer everything a full ATX board offers in regard to performance (not expansion, obviously). Even the latest 1155 Mini ITX boards from ASUS allow for extremely overclocking of an i7 3770k and the accommodation of the maximum amount of ram for that chipset (granted only two slots), and a 16x PCIe GPU.
Graphics cards are using less energy, giving more performance. CPUs have been doing the same for years. This is called progress. So give me my ultra thin device that is super fast. I don't care how much room is available on my desk. I'll take a thinner iMac!
If I want something modular that can accommodate the latest and greatest hardware, then I would be building another PC in a full ATX tower, not complaining on an iMac forum about how thin an All In One computer has become.
/end rant
Now as far as speculating whats going on with that leaked image, I just want to make a few points:
1. No ODD (thank the gods!)
2. Thats a 2.5" HDD
3. Interesting to see the CPU socket toward the top right of the computer. Previously it was toward the bottom left.
4. Looks like those black items on the left and right may be either fans, or speakers, or both. Who knows?
5. Wonder what else this picture isn't showing? Where is the GPU?