Joe - I know that I have some bias against Par 5s, some inherent dislike of them. I haven't played many great/famous courses, but I have played many courses and therefore many, many Par 5s and for the life of me can't remember with fondness more than just a very few. But that bias notwithstanding, it does seem to me that architects make an unenviable task (i.e. designing a terrific Par 5) even harder by thinking -- if in fact they do, which is why my OP is a genuine question -- that they can create/salvage one out of mediocre ground. To me it would seem far easier to design an excellent Par 4 over such ground than a Par 5 -- but that's not the choice most architects seem to make most of the time. (Again, maybe my impression is flat out wrong on that). I'm not sure if your idea would fly, but it may be unnecessary, i.e. just cutting in half the standard number of Par 5s and cutting also the number of Par 3s and instead having many more Par 4s would do the trick for me just as well. (One bad result of my bias is that I have little interest in playing any Stanley Thompson course, what with his tendency to have lots of 5s and 3th. I'm sure I'm missing some wonderful golf/golf courses -- but I can't bring myself to thinking about playing six 5s and six 3s, and indeed that kind of design just seems, well, lazy).
Peter