Don't get me wrong, I think Shaq would be dominant just like he was in LA, I was objecting to the idea that he'd be better or more dominant today. He may have been, but he also might not have been. There is no way to know that.
Shaq got hurt his last year in Orlando and was never the same physically. He bulked up a lot after that and stopped running the floor as much. I just don't think his frame could handle the svelte 390, he needed to be 325+ to stay healthy enough to play in the post, which is why he changed things up stylistically somewhat in LA. Phil obviously helped a great deal with that as well.
I look back at Shaq's last year in Orlando when they got swept by the Bulls, and I just remember Rodman giving Shaq so many fits in that series. His small, yet very strong, frame just bothered Shaq. I think he got bigger after that so he could better use his size. He got bigger and stronger and that is when he really started to dominate inside. Early on he was a very big man, but played more of a finesse style (and yes some of that could have been coaching).
All that is to say, I don't know how Shaq would have translated today. Obviously he'd still be an all time great, but I don't really know if he'd be better. Different, sure, but I don't think he could play like Giannis. Doesn't have the skill to do that. He'd be bigger rhan anyone else, but that doesn't mean he'd work better on the modern game either since he was bigger than everyone else when he played.