Tray-loading optical drives are dead and gone as far as internal models go. Quite frankly, I'll be shocked if Apple includes an optical drive in anything but a Mac Pro from now on.

Colors... there's always spray paint - which is the only way you'll see anything but white or black, IMO.

Given that SSDs are already options in the existing iMacs, I would expect that they'll be made standard in future iMacs (not the rumored refresh this year) - with a regular HD being the BTO option.

Matte screens are dead and gone... don't hold your breath waiting for them to return. You'll have to buy a 3rd party external monitor to get that, and I suspect those will begin to be very difficult to find within the next year or two.

Thinking about it, I'm not really sure what Apple can possibly do to release a totally "new" iMac moving forward. They can put faster processors in there, increase the SSD size, add more RAM, and increase the size of the monitor a bit. But realistically, the monitor is about as big as most general consumers would want on their desk right now, and the thing is already fairly thin.

Maybe a better, more adjustable stand. That's something I would like to see.
_________________________
The Graphic Mac - Tips, reviews & more on all things OSX & graphic design.