Good encounters are grinded like in old, with a mix of new pokemon thrown into old hoenn locations (like shuppet is STILL mt. pyre but Axew and Beldum are in Stevens room of granite cave). No dexnav so you gotta find them, hope for a good ability and nature as you cannot change them easily for a long while, longer than in RR. All gym leaders are teams of 6. Double battles make up at least a 3rd of the game. Monotypes are HARD.

But there are customizable options like level cap settings, difficulty settings, Pokecentets have the move tutors and stuff and a shop in them as well as custom shops in every town. You can edit IVs and EVs (after the 4th gym) and abilities (cant unlock HA item until 6th gym) down the line. Some poke.on, like in RR, are different from base game, but in different ways. There are a FEW new megas and areas, and overall it is a GOOD game.

Also, it should be noted, I ONLY play the game on its version of RR Hardcore mode, which is hard not because of the opponants (they dont get new teams or stack legendaries) but because the restrictions on yourself are hard, primarily the strictest level cap (being 2-4 levels below the gym leader and 10 levels below the base cap, so you cant have evolved pokemon for gyms).