So, granted, I haven't played elden ring yet since I don't think it'll launch on my PC (GTX 670), but based on his other works I would be hesitant to put him up there with the Miyamotos and Suzuki's of the world. He seemingly created a niche subgenre and really nailed it (I got on the demon's souls train in college while my roommates were losing their minds over modern warfare 2). That being said it's pretty iterative work. I don't mean that in a negative way, but looking at the choices I'd personally rank someone like mikami higher based on the pure joy that is resident evil and god hand. Kamiya in that realm too has done a superb job with stuff like DMC and Bayonetta, but also branched out and created special games like Okami and Viewtiful Joe.
I think the itagaki comparison is one I can get behind. Masterful execution in a genre, although I would say he's surpassed him by now. Is he the lead on the armored core games as well.
There's certainly nothing wrong with being in that tier though. Impressive stuff, I just would call him the greatest of all time. Suda51s is my favorite game director of all time but I don't think he's anywhere near the best of the best.