Mark,
An important factor that has to be taken into consideration is how the hole was designed to be played when it started out. For example, a shortish par four of about 340 yards or so from the blocks has to have an element of defence for it to become a well earned birdie, and likewise a decent par. A hole of this kind often requires the player to either lay up to a yardage that is convenient for the second shot, or to avoid obstacles such as fairway bunkers, croos water or even to slot the ball into the elbow of a dogleg. More often then not with most well designed holes, there is an ideal landing area which to achieve from the tee. Therefore, the aim from the tee is to hit the ball the adequate distance to achieve this, after doing much calculation as to whether or not it is possible. We can conclude from this that most players can reach the area from whichever tee on a hole of this length, and that it is just a matter of choosing the correct club and type of shot.
However, the back tees do matter when the back tee is set at a different angle to the 'medal' tee, making the hole entirely different. My theory on this is that the players playing from a back tee on any type of hole are being asked a different question. Although the players will usually be able to hit the ball the right length to keep up with the head start of the normal men's tee, they wil have to take into account a hint of shape to achieve the correct destination. The point of this seems that the championship tees are keeping the players on their toes at all times, turning the test of the course up a notch, which seems natural for the standard of player that deserves to play from those tees.
The average player would be at a disadvantage on a hole much like the 13th at Augusta. A par five only a touch over 500 yards, and not too much of a length problem, although strategically it is certainly food for thought. The shorter hitter will have to deal with not being able to see all the way around the corner from his drive, thus making his decision as to where to lay the ball up guess work in terms of line. On the contrary, the longer player can try to sling the ball round the left hand dogleg to open the shot over the creek. The reasonable fairway here also opens up the possibility of the longer player snatching a stroke on the average hitter, on sheer power and not ability.
I am much in favour of longer tees when necessary, but not for the sake of length. Sometimes it seems that courses are only lengthened to be able to boast a 7000 yard plus number on the scorecard. The way the longer hole can help as opposed to hindering the golfer's experience, is when the challenge of the hole is concerning strategy over power only.