Many jets are quieter than the older Dash 8 100s and 300s that Air Canada formerly operated out of the island.
I can't say how STOL jets compare to the modern Q400s, though.
Either way, I think restrictions should be based on noise level rather than defining a technology.
The logic of basing it on noise level rather than a defined technology is hard (impossible?) to argue with but having the restrictions based on a technology line does build a bit of public comfort over the restrictions. It is easy to point to and say "see no jets" rather than "see, no planes that, in normal operation in a test lab do not produce noise over a certain level".
As someone that grew up near, and still lives somewhat near, Pearson I can tell you that a big problem they have with the public is the perception that the rules around flight times, flight paths, etc are too technical and, therefore, vague to the public/laymen. So when I lay in my bed at night and hear a plane at, say, 3 in the morning I am discouraged (not that I would) from phoning and saying "hey, is that allowed". For me it is not a bother but for some I know it has built up a level of distrust/doubt.
In the case of the Island it is easy for them to just say "no jets" and as long as no one sees any jets landing there they are comfortable that the rules are being followed (even if they are not comfortable with the rules themselves). Since there aren't many (any?) jets that could land there at present it is a convenient rule to have. I also think it is why the runway will not be extended as it will open up the argument from people saying "see, this is the thin edge of the jet wedge" and would be tough for any politician to support.
I think the only way the runway gets extended is if a plane goes off the end of the current runway and the subsequent investigation says "this airport is unsafe without a runway extension".....and I don't think anyone wants that to happen.
