did I use the word jealous once?
I consider a revamp to be something small...like pb -> mbp change. Different keyboard and maybe a slightly different look. How much can they really even change? Make the hard drive user replaceable, remove the plastic edges, change the keyboard maybe....
small changes. Revamping an old design.
I wouldn't consider those small changes, but that's just me. A revamp is bringing in a magnetic latch and changing the internals slightly, maybe even getting rid of the grey border that constantly falls off, like the PB --> MBP change.
A redesign is putting in the God awful keyboard from the MB/wireless keyboard, changing the case materials, making it look like the Mac Book Air or some other notebook, etc.... Along with changing the internals like the iBook --> MacBook change.
They will change it eventually, they don't have to though. And personally, it's been that way for a very long time, much like the G3-->G4-->G5-->Mac Pro. They "redesigned" the case and internals but the same basic design is still there. The handles, placement of optical drives, ports, structure of the tower hasn't changed since the G3 IMHO, it's just been refined to the point of perfection (the Mac Pro).
The only thing they can do to change the tower is to make it accept more internal hardware and more ports, and make it more tool-less. Same thing with the MBP, just give us more hardware or slightly refine the design.