Yes, it's still like that, because grinding has been a necessity in Pokemon since the beginning. It's built into the essence of the franchise. However, they have changed it up and made things more bearable for those who get bored or discouraged by grinding.
In X & Y they decided to give you the Experience Share item really early on, and Sun & Moon does the same. This can significantly cut down on grinding time if you don't care about EV training.
Essentially, whenever you knock out a Pokemon, if you have the Experience Share turned on then every Pokemon on your team will gain experience points. You can turn it off if you find it makes things too easy, but since you got bored of grinding previously you might want to keep it turned on.
Additionally, you can have a Pokemon on your team hold a Lucky Egg to double experience earned. Unfortunately in Sun & Moon you don't get this until after you already beat the game, but you can probably buy one from the TBT Marketplace since some people seem to sell items in their shops.
If you don't know what EV training is, here is an explanation. Every Pokemon, when defeated, contributes Effort Value points to the Pokemon that knocked it out. Say you knock out a Machop. This gives whatever Pokemon that knocked it out 1 Attack EV point. You can earn a total of 510 EV points per Pokemon spread among all stats (HP/Attack/Defense/Special Attack/Special Defense/Speed) and each stat caps at 252 EV points.
You don't need to worry about understanding EVs just to run through a game and beat it. This is more relevant if you intend to battle online against other people, in which case you want to utilize EV training to be as strong as possible to be competitive. The only reason I brought it up in the first place is that if you do want to EV train stuff, if you use the Experience Share then it might cause problems if the other Pokemon on the team aren't going to benefit from the particular EVs. If you knock out another Machop but one or more of your Pokemon is a Special Attacker, then getting that Attack EV isn't optimal. Hopefully this makes sense.
As for whether there is anything you need to know, not really? It's dialogue and plot heavy so if you want things to make sense, pay attention. Also, turn the volume up because Sun & Moon have some great battle music. Additionally, since you've been gone, the Fairy type was introduced. Fairy is immune to Dragon and is super effective against Dragon, Dark, and Fighting, but is weak to Steel and Poison.
I hope you enjoy your trip to Alola!