I spent a ridiculous amount of time trying out every feature in Pokemon Y a while back, so when Pokémon Sun came out I wasn't in a big rush to get it. Eventually I did, and it's taken me more than four years to finally finish the main story. Even though critics raved about the games I found the updates to be incredibly minor. The Pokemon games aren't known for being super innovative from generation to generation, but as with my playthrough of Pokémon Pearl I found Pokémon Sun to be an utter snoozefest (on more than one occasional it literally put me to sleep!).
It's a little difficult to pinpoint exactly what makes Pearl and Sun so dull compared to other iterations, such as Black and White and X/Y. I think part of it is is that there weren't that many new Pokemon (only 81 apparently). Introducing Alolan forms of Gen 1 'mon was a lot of fun, and I also liked that a lot of the new Pokemon had unique dual typing, but the story bored me to tears, and trials pretty much just felt like regular gyms. Looking over the list of new features the games included there's nothing much that grabbed me, except the stuff with the Ultra Beasts which had interesting-looking designs, but that's pretty much all in the post game.
I don't really have high hopes for Pokemon Sword and Shield, although the setting looks fun and it will be interesting to see how the series takes advantage of the added horsepower of being on a console rather than a handheld. I actually already started checking that out even before finishing Pokémon Sun, but I can't say I'm that eager to jump into more of the same old formula I've been playing for decades now.