>>57923299It's mostly coupled with the whole "coming of age" thing that Norman sets the player out to do as soon as you reach Petalburg, refusing to battle you until you've proven you're worthy of taking your first true steps into independence.
Sure, you've trekked a dormant volcano on the way to earning your right to challenge Norman's Gym, but it still felt like a very controlled environment overall.
After you beat Norman and get your Surf privileges though, the world vastly opens up suddenly, and instead of following the advice to head towards Fortress, you can explore ocean routes as you see fit rather than being limited to a scripted boat ride, and the routes to Fortree (later extending to the ones that lead to Lilycove) themselves are this long stretch through a dense rainforest where the grass grows taller than you've ever seen before, having trainer classes you've only barely seen prior that are now becoming commonplace and evolutions you otherwise only saw in your own hands or the hands of trainers.