One nice thing about a park like CP being a premier regional park/resort is that their pricing is sort of in the fat part of the bell curve, meaning that, generally speaking, anyone squeezed out of the lower end by higher priced premium products can be replaced by becoming more enticing to folks on the other end of the bell curve's tail. Or, as you put it, "Raising the price could reduce the number of people using Fast Lane, potentially creating shorter waits and a better experience for those who continue to purchase it." I think that's the main takeaway here.
Previously, All Season Fast Lane was just way too inexpensive, leading to saturation and thus a poorer experience for everyone, including and especially annual multi-day visitors who may drop a substantial amount of money each year at the park, as compared to locals who could "justify" the ASFL by using it many, many times throughout the season. Hopefully this price point pushed locals and other lower-per cap visitors away from it.
I do want to push back on this just a bit, because if locals and other frequent visitors were using ASFL on a regular basis, which I would guess was the case based on this price increase, pricing some of them out may actually make standby lines shorter, rather than longer, since there will be fewer people lapping them from the FL/FLP queues.
In general, though, it's refreshing to see the park seemingly setting the pricing to where it should be, correcting for the bargain-pricing strategy of the Gold Pass. CP, and to a slightly lesser extent KI (and Carowinds and Canada's Wonderland), should be priced as the premium products they are, rather than become de-facto baby sitters and glorified FECs, which harms the brand and can result in a death spiral.