One of the differences between pinball and other games/sports is the random factor. Most games/sports have a higher skill to random ratio than pinball. It's the randomness of top players having houseballs/bad breaks/etc that makes things interesting and gives less skilled players a chance to win on a given game.
I'm not opposed to people trying to introduce a handicap system as long as it increases the fun factor for all involved. That's the important part. I just think pinball has enough of a built-in handicap in the form of game randomness, especially as you go farther back into SS and EM machines.