If it has the same Exp share as X/Y then that'll immediately set the difficulty level to Super Weenie Hut Jr. Turn it off for regular Weenie Hut Jr.
lmaooo
But I have a few things:
1) The Physical/Special attack split happened directly after Emerald. This is probably why most of us find new Gen games to be really easy. Now certain moves instead of certain types are either Physical or Special attack, so your stats have more utility and versatility. It used to be if a Fire-type Pokemon had all fire-type moves, their regular Attack stat would be rendered completely useless. Now, it depends on the move you teach it, and the game will
tell you which kind of move it is so that anyone can battle relatively competently.
2) Exp. Share obviously
3) POKEMON AMIE/SUPER TRAINING. I didn't know how hard the game would be so I just maxed out all of my Pokemon on Amie when they were babies. We eat every team we come across whole.
4) Stat boosts/Creeping up on Pokemon. It is very hard for me to find a Pokemon nowadays with no stat boost whatsoever in at least one category. Some Pokemon, like my one Marowak, have almost perfect stats and I had no difficulty finding that Cubone at all. It was just sittin' in the grass, and not, mind you, as one of those shaking ones you have to creep up on a la Pokemon Black and White. Those have an even better chance of having really good stats. I caught a Surskit by creeping up on it (once ultra rare, now just hanging around in the grass). The stats on my Masquerain make it way too powerful- it one-hits any Pokemon a level or more underneath it.
5) We've played the game before. Prior experience is going to make you better at the game. If you're anything like me, and have played the original at least 30 times, probably more, ORAS is going to be a piece of cake for you. You might finish it in a day. But think of how long it might have taken you to beat Pokemon X/Y since you'd never played it before. You already know where to go and what to do- no wonder it's an easy game.
At least, those are my proposed reasons. There are probably more- maybe some of these are not direct contributors.