It's... Pretty tricky to go into it without going into an extremely long rant or super-duper picky detailed breakdown, (hell, there's a seven hour Youtube review with all the games' problems detailed route by route which even I considered excessive) but the shortened version is that compared to Base RS, it was severely dumbed down difficulty wise, removed a lot of the challenge, even with EXP share off, while also removing some side activities such as the Safari Zone, Battle Tower and Contest Pokeblock minigames for practically no reason. Contests were also made too easy to the point of them being practically autowin and removing a lot of the skill that made them a worthy postgame to begin with (RS was VERY limited post-game wise, akin to XY, so the contests having challenging merits to them were the saving grace)
Of course, Emerald came along and expanded the Safari Zone, Contests, and Battle Tower mechanics while adding even more new things like gym rematches, which is why most people play that over RS. But ORAS's biggest sin is pretty much acting like Emerald never existed by not only removing the expansions Emerald added, but making it so that the stuff they expanded to begin with were barely there. Considering XY's similar lack of a post-game, take RS's lacking post-game and make it no post-game save for a legendary hunt, the traditional dex hunt and a recycled cheating Battle Maison, (that they didn't even bother to update for Hoenn Trainers, so everyone there is dressed in Kalos wear and uses Kalos-centric teams) and you have a remake that basically does the opposite of what HGSS, FRLG and even freaking LGPE does.
Like, I thought LGPE was to be ORAS 2 since they were so adamant about dumbing stuff down and doing silly restrictions for no reason, like removing abilities and held items, but then I rented it and was shocked that a lot of the stuff that made me enjoy Yellow was still there. The game still had some sense of difficulty even with EXP all forced, to the point I got destroyed a few dozen times, the game doesn't really do much to bug the player outside of saying "hey, here's how to do this" to know what to do next, and the only things really missing are Safari Zone (But all their unique mons are in new spots) and Pikachu Surf Minigame. FRLG has more to do, but LGPE is still more focused as a yellow remake than ORAS are as RS remakes. So that's my hope in remakes are in a pretty rough spot since they went from the killer HGSS, to the lacking ORAS, to the solid but safe LGPE.