Exactly. There's nothing wrong with the global way of how the OS X UI currently works. There've been a lot of substantial changes under the hood in Leopard and Snow Leopard, but these aren't the things user really notice with their day to day computing. All that's left is refining all the little things, that in the end add up to quite a substantial change in how easy and fast you can do things.To make drastic changes just for the sake of change is ill advised. [...] I think the average user is more concerned about 'apps' selection, trouble-free operation, and device integration rather than a jazzed up desktop.
A sudden and complete overhaul of the (entire) UI is the last thing anyone should want. Look at Mission Control that's being used as the new Exposé in Lion. Just a single feature that was changed, but it has a huge impact on many people's workflows, and everyone is freaking out that this is suddenly different. Imagine how this would be if suddenly everything was changed. No thanks.