I'd like to know what a Mac Pro would be like without an ODD. Hopefully, it'll bring PCIE-E 3.0.
PCI-e v3.0 is provided by the CPU package. If they move to Xeon E5 or any 2012 or later Intel offering, it will have PCI-e v3.0. By 2013, the only way to keep PCI-e v2.0 is to commit either to AMD or Intel chips from that are minimally about 2 years old.
The Mac Pro has two ODD bays. Minimally they can get rid of at least one without changing even having an ODD as an option. The fact can chuck one and still have a left over means there would have to be some deep seated "war on ODD" being engaged by Apple. However, could loose both if Apple is looking to shaves 2-3 inches off the height and move some internals around.
As for the iMac, wouldn't be that surprised if there's no ODD. Should be quite a bit smaller.
Smaller is a dubious design move. The only practicall dimension they can reduce much is "thickness" (the height and width are driven by the screen and some of the requirements to place components in the "chin" ). iMac currently has thermal issues when pushed extremely hard. Two much better uses for the ODD compartment would be
i. Additional fan(s) ( and possible side vents ; new fans could put out the side, while others still push bottom-2-top ... )
ii. smaller fan and HDD or SSD (i.e., two drive set ups where don't have to stack the SSD in ad hoc location in the enclosure. )
iii. a socket/door that allows access to HDD ( huge leap in serviceability. Pop 2.5" drives in/out instead of optical disks. )
Thinner could be done by fusing the glass with the LCD panel without having to much with the back half, "computer" section.
Would also like to see Retina, but that many pixels on even the 21.5 iMac would probably be hard on the GPU.
I doubt anyone wants to see the increase in pricing "Retina" 21.5 and 27 panels will bring. It would be "doable" by the GPU. What would take a huge hit on is running 2 and 3 monitor set ups. Once loaded down with "twice as big" embedded display adding large external ones will expose the limit "torque" the iMacs have in doing even mid range 3D over an extremely large number of pixels.
2D (and OS X disco animations in the Finder ) would work but limitations would be exposed.