I agree. There's this nifty thing in ORAS with secret bases called "Blissey Bases", which makes grinding so much easier. You can register them via QR codes, and they contain three Blissey who use Healing Wish (though, you might have to take down the last one on your own, as only a couple actually have the pokemon hold a Toxic Orb), and they grant about 6k exp per. I lost a couple team members before my E4 battle (it was a nuzlocke) and had to train up two new ones; luckily got myself a Clefairy and a Growlithe, then just took them through those bases.
It took a couple days, yes, since you can only battle once per day and it takes a day to be able to battle someone if you register their base via a QR code...but it's much more satisfying knowing you won with the pokemon you trained.
Steven was still tough, no doubt about that, and my pokemon were around level 60 when I faced him. My Arcanine, Roy, was the MVP for that fight, and especially the final bout; though if that Mega Metagross of his didn't have Giga Impact, the fight might have gone much differently for me since the recovery time gave me a chance to heal.
Pretty much alternated between healing and attacking, but it only took two Heat Wave attacks to take it down, and I didn't lose any of my pokemon.
