Mmm.. I don't buy that the tradeoff is a bad one - for most users.

I think it's vastly more common and natural for the majority of users to want to be using one application at a time... and for that purpose, the mac GUI paradigm is the best solution.

You (and I, and most unix geeks) are (unfortunately for us) unusual in that respect.

I agree, Expose + Spaces is nowhere near as good as proper X11 window manager and mouse fu. :-) But the latter is most definitely a metric boatload more complexity than the average user bunny wants or needs.