I haven't played Sword and Shield admittedly, but Pokemon isn't the kind of game you play for the story in the first place (even if SwSh is probably subpar on that department even by Pokemon standards). The only Pokemon games I remember having a good story are the Gen 5 games.

When Pokemon Blue and Red came out it was a good and unique story and had memorable characters (Ash, Team Rocket etc'). I just didn't exactly expect that story premise to be recycled 20~ years later.

I'm pretty sure the roaming pokemon wasn't a thing they added because of the fans, but because they already had it from Let's Go. Whether it was ready or not by the time of the first trailer, I have no idea. And about the graphics, Sun and Moon had a decent amount of slowdown in certain areas (especially in double-triple battles). That continued in Sword Shield, plus added some more issues, even though the Switch is vastly more powerful than the 3DS. Also, the 2D sprites allowed for environments more complex and detailed, plus they give you an easier time to suspend your disbelief (Pallet town is three houses, that's fine on a 2D environment, but a town with 3 houses in a free roaming 3D game is harder to swallow). The most developed a town has looked in the 3D games is Lumiose City, back on X/Y.