Tilt screen, but not raise
Um, I think part of the significance of the latest iMac's has been the merging of the screen and system unit as 1, and it's here to stay. Poor decision to you maybe, but the sales numbers speak for themselves. You're basically asking for a more powerful Mac Mini.
Actually, I've owned 2 iMac's (G3, G5) in addition to Power Macs (towers) and the iMac has NEVER been able to raise up and down. So, a child sitting at a desk can see the monitor fine, but an adult using the same computer must look down.
There is no reason why the monitor could not have a telescopic arm that re-positions the monitor up-and-down depending on the users preference.
That is my #1 complaint about iMac's.
As for sales. iMac's do better than mini's and towers since they have the right price point -- due to their components. Average users certainly do not need Xeon processors. However, mini's are a bit underpowered.
So, the happy medium has no choice is allowing one to retain their previous monitor. If you have a monitor you like, you get the choice of underpowered mini or spending $3,500 for a workstation level computer. No in-between.
Eco? Yes, new Mac's are better than the rest. No PVC's, etc. However, the term "Reduce, Reuse, Recycle" means that if you have an old Cinema Display and want a new computer, you can not go with the happy middle ground as iMac's are bundled with the monitor.
My last iMac G5 has a great monitor, but its getting slow, has always been noisy, inserting a CD requires "special assistance" in loading, and while the monitor is still in perfect shape, the computer should be replaced. It would be nice to not have to get rid of 2 components when 1 is bad.