I had clear goals in sight-building plans, the marsh, the pass-but either my Pokemon were too low or the cost was too high.
When my Pokemon were above level 10 but below level 20, things started to feel a little grind-y.
Since the fisherman pretty much gives you the poles anyways, why not just have him add them to your inventory instead of buying them for 0$?.
This would be kind of a big undertaking, but have you considered doing some recolors for the player's sprite, depending on their type? I think it'd help make the gym feel a bit more cohesive-Red standing in a green room doesn't really feel like any particular type.
I imagine you already have this planned, but I think seeing the trainers approach the player would help make the gym feel more lively, rather than just being the player standing in an empty room.
I think it'd be helpful to have some sort of calendar that displays what day the player's on, in case they have daily tasks they want to do.