I disagree about his grappling being as tested as it could be, but I seem to be in the minority in thinking this, so it's all good. Volk kickboxed with ilia, Hall doesn't have the takedowns to test ilia, mitchel is a BJJ guy with highschool level wrestling and before he got the shit beat out of him on the feet, he held ilia down on the mat and ilia had no answers. Giving up a takedown isn't a big deal, but having zero answers from his back is a big red flag to me. I've seen illias pre ufc fights too, and he was held on his back in one of those fights with no answers as well. We haven't seen him against wrestlers other than emmet, who didn't wrestle and volk, who didn't wrestle. I don't blame ilia either because this era of FW has very few wrestlers worth a damn.
He has done very well with what he was against, but I just haven't seen the grappling that people are so highly touting. That said, what he has shown us has been more than enough to get the job done.