The problem with Lee though PP, is that he's so inconsistent. I have no issue with him being a runs truck if he takes wickets (though you look at express bowlers in the past they've had low economy rates as well as good averages). The problem is he doesn't take wickets and he doesn't keep the pressure on (barring the odd instance in Adelaide with the old ball). Most importantly for me, he doesn't seem to be able to consistently out-think a batsman - to bowl to a plan (like he did with Freddie). Either his execution of the plan is lacking, or his temperament gets the better of him and he abandons it.
I guess if you bowl that fast you will knock over most mediocre batsmen because they won't even be able to see the delivery, but quality batsmen will be a lot harder to dismiss.
Too often Lee acts as a release to pressure, rather than pressure in itself. If you think about it, he's got some great bowlers at the other end to create pressure of their own (eg McGrath, Warne, Clark, etc). It's not like he's trying to do it all by himself.
I have no issue with his work ethic, but he's going to have to be more intelligent, and get some more variation, if he wants to bowl into his 30s. Once he starts to lose pace he'll have to adapt, like the greats did, like Lillee and Marshall and Waqar and all the others.
BTW, Symmo with his dibbler dobblers has bowled in a more intelligent manner than Lee - he just worked away at GoJo and finally got him caught at the gully for a duck. 6-114.