From my point of view, I agree that most of the best short par fours would lose a lot of their luster if the tees were moved way back. And it probably works the same way if a long hole is converted to a short one (e.g. the 14th at Torrey Pines South in the '08 Open).
I don't think most courses can be too elastic because at some point decisions have to be made in the design process to do potentially interesting or bold things and these features are often dictated by length of hole. If every short par four was 100 yards wide, the interest that comes from having to execute a straight tee shot would be lost.
But, a hole like Riviera #10 is fantastic because it is wide, but requires real thought and execution. If it was 430 yards and played to that green there would be problems. If every hole was designed to play from a myriad of distances (eg back tees at 420, 370, and 290) you might have to make the green a more uniform size or shape and provide gentler undulations. You could still end up with a great hole, but it wouldn't be the same hole and it certainly couldn't be a copy of Riviera's 10th.
In my opinion, I think many of the best holes (of any par) are better when they are played from their original or intended set of tees and have a relatively simple concept. If someone tries to do too much and fit too many options or tees into a hole, it's hard to maintain the integrity of the design from all the different lines of play and yardages. That being said, I would give a lot of credit to any designer who can build holes that maintain interest from a variety of lengths and angles without hurting the quality of the design.