I suppose I'm in the minority that actually likes the non-Gen III ish feeling in ORAS? I mean, to me, the original R/S games were really dry to me, and if you take out the mega-evolution and primal reversion aspect of the games, then that's all you're really going to be left with: just dry content. While I understand that some of the whole backstory behind Primal Reversion and Mega-Evolution just seems like unnecessary "fluff" for the sake of adding more to make the games more interesting, some of it is actually intriguing (though I suppose it really depends on the person and whether or not you care about the whole mega-evolution aspect; I most certainly did, so there's that).
I actually liked learning about Kyogre's Primal Reversion and how it connects to Mega-Evolution, because it made me feel like I was actually going somewhere (i.e, making some kind of progress) plot-wise, where my reaction was generally "oh shit, now I'm getting to the meat and bones of the games". Back in the original R/S, I can barely remember a thing that stood out to me as particularly interesting or intriguing, and in these games I can actually get a grasp that Team Aqua was after the power of Mega-Evolution, as well as Primal Reversion (Kyogre) and you, the main character, is going to stop them and save the world, as is typical for R/S.
Now, I completely actually understand the whole thing with Steven's dad going on a tangent about the weapon that destroyed Pokemon (and I think some of humanity? Maybe it destroyed most of the Pokemon population, idr the entire thing), but I believed that in itself had more to do with the general plot of the Delta episode which was relevant to that in particular. I think the games were trying to remind you of what took place in X/Y and directly connect it to the events in the Delta Episode to give you an idea of what's taking place and set the foundation for the Delta Episode, as well as, in a sense, give you a sense of urgency that "ok, this is some serious shit if he's telling me about some story years ago, even if he is a rambling old man".
tl;dr: I generally feel all of the "kalos references" and whatnot actually made ORAS more interesting. What else would you have substituted it with, given the amazing lack of "meat", so to speak, in the original R/S games? There's literally nothing that was memorable, not even during your first meeting with Steven and nothing really happens until probably after you beat Fortree's gym, whereas in ORAS you actually managed to encounter Team Aqua/Magma quite a bit. Maybe I'm wrong, it's been years since I've played the original Gen III games, but I feel it's a bit out of left field to say that mixing in a bit of Kalos' plot was unnecessary.