Is it worth playing Pokemon Sun? While the simple answer used to be, "If you enjoyed previous Pokemon games, this is more of the same," that's no longer the case. There are new features that are driving trainers up the proverbial wall.
One such feature is wild Pokemon's ability to call for help, bringing a second foe onto the field. Sounds neat in theory, until you realize that you can't throw a Pokeball unless there's only one foe, and every time you KO an opponent the one left standing can instantly call for more backup leaving you in a never-ending fight, unable to catch your prize. It's been quite the maddening experience. A one turn grace period would have been greatly appreciated.
Another oddity is the removal of gyms. These have been replaced with trials. So far, as I'm only just getting to the third island, these trials have been kind of odd. They've ranged from collecting ingredients to spotting the differences in dances. It's been fairly weird. There are still battles to finish the trials, but they seem to be more of a backdrop than the main event. Unfortunately, as a long-time fan of the series, this is how the Pokemon feel in this game in general: they're a backdrop. The game itself is very slice-of-life with Pokemon feeling like they were added as an afterthought.
Trading from previous games is also currently not an option. Pokemon Bank has an update scheduled for January, but until then there's no way to "Catch 'em all!" That said, when the update does go through, you'll be able to not only trade from Black and White forward, you'll also be able to trade from Red, Blue and Yellow if you've purchased them on your Nintendo 3DS. That's a pretty nice feature and will almost make paying ten dollars for an almost twenty year old game a little easier to bear.
Now onto the good. Global events are pretty nice. The new Z-Moves are the spiritual successor to Mega Evolutions and can only be used once per battle, but they are insanely powerful. Some old Pokemon got new typing, such as an Ice-type Vulpix, an Ice/Fairy-type Ninetails and a Dark/Normal-type Rattata along with quite a few others.
Along those same lines, one of my favorite parts of this game are the types that you can catch in the early game. It's very easy to get a well balanced team very early on, as opposed to previous titles where certain types simply didn't show up until halfway through the game or later, suddenly forcing you to switch out members of your team who had been with you from the start. Given that the overarching theme of the game is growing a bond between yourself and your chosen partners, this is definitely a plus.
So, is it worth playing Pokemon Sun? Definitely. Just remember to bring along an open mind for the trials and a fair helping of patience. You're gonna need it when that last Pokemon you need to complete your island Pokedex decides to spawn an army.