Chuck
IMO the par designation is of no real architectural concern. Either the hole is good or it isn't. Of course, how the hole fits in with the remainder of the course is of great importance. For instance, if there were a few other demanding par 4s on that side of the card (or running a bit too much in a row) or if there really wasn't a par 5, then I may consider keeping it a par 5 just for these reasons. Many times its good to offer breather holes so long as there is some sort of sting in the tail. There is no point in designing a blah hole - afterall there are only 18 of them. Some may consider the actual decision making about par designation an architectural matter and there may be something to this at least to some degree, but I would hope archies don't spend too much time dwelling on par designation.
Having said all that, I haven't seen too many courses which deviate very much from the par range of 68-73 (for men) so there must be something about par designation which influences archies. For instance, it can't be dumb luck that it is a rare case when say a par 4 doesn't appear on one side or another. If this sport of case presents itself in the land most archies will move dirt to create par 4s. I'm not saying this is necessarily bad, just that it may be a contributing factor to homogenized designs. In all honesty, I don't believe archies really think outside the box this way. Either that or they don't believe an outside the box design would be accepted.
Ciao