[vizeroth]

Other than the appearance, a great deal of the design goes into cooling and noise reduction. Many Macs can do quite a bit without spinning up a fan, and the more powerful machines usually have more complicated mechanisms to make this possible.

Yes, it's easier to do all of this with a bigger footprint, but Apple has a hard time pleasing people with the Mac Pro regardless of which direction they go, and at this point I don't think they would win over many fans by pushing out a standard tower.

[nottorp]

No current Mac, with the possible exception of the trashcan, can do the "quite a bit" that a pro user needs without spinning up a fan. Keep any of them at 100% CPU for 5+ minutes and see for yourself.