Moreso the fact that they haven't recorded any new dialogue for him since his voice actor died. I don't think they WANT to write Igor out, he's the single most consistent element across all of the games. But given that it seems like they're unwilling to replace his character so far, I just think that he has at least some chance of being cut entirely and replaced with some other velvet room attendant.
I hope not though. Hopefully they can find a way to respectfully replace him and keep the character in the games since he's so iconic.
Velvet room will most likely stick around, it's just Igor that I think might be written out. Kirijo Group is so definitively a P3 thing, and Shadow Ops were introduced in a fighting game spinoff series. I think the fact that P4 stepped away from nearly all of that is a good indication that Hashino's team wants mainline games to be separate, insular stories. Even P3 ignored most elements of 1 and 2, dropping the Philemon vs. Nyarly element entirely. I think Hashino's team wants to focus on other things. It's a guess, but I just don't see his team as one that retains a lot of elements. Bringing back Kijiro and creating the Shadow Ops were more a plot contrivance to have P3 characters show up in Arena.