As a pilot, I'm curious about your statement that Pearson has "shorter paths today than before". A quick look at the Toronto terminal area aeronautical charts that I've saved over the years shows no changes in Pearson's control zone or waypoints. Large aircraft require stabilized (straight) approach paths several nautical miles from the runway thresholds, and the area restrictions are designed to accomodate this. Minimum altitudes are prescribed up to 26 nautical miles from the field, which includes areas as far as Pickering to the east, Newmarket to the north and Hamilton to the west. Base turns (where the aircraft turns to "final") are done at approximately 15nm. From the east, turns are done over the DVP. From the west, over Burlington. Special exceptions are made for diplomatic or military aircraft, or for emergencies. I'd like to know where these shorter paths are. Pearson has the tightest controlled airspace in Canada. Minor changes are made only after years of analysis.
If anything, the only change that I've observed is the tightening of restrictions in the island's control zone to ensure that the tower has firm control over any aircraft flying through its area. As an airport gets busier, I have never seen an approach path shortened, only lengthened as approach controllers need more and more time to sort out the congestion.