Good wrestling is all about the shot, reshot, level change, reshot etc. ad infinitum. Wrestlers finish the take down on their sixth attempt, not the first. This many reshots and level changes are just really dangerous in BJJ.
Sure Rustam Chsiev looks like he's doing pretty well with his wrestling, but how does it work against the actual elite? I think it's like Eddie Cummings with leg locks. If you have elite level wrestling, ok, you can make it work against most guys. At the elite level though it's just not effective.
Otavia Sousa takes Kron Gracie to overtime by completely stalling out the whole match on his feet just so he can attempt to beat Kron on takedowns. Off of Otavia's first takedown attempt Kron immediately picks up the guillotine and subs him. This kind of thing just messes up good wrestling. You have to be able to play around. Fake, fake, fake, shot, reshot, level change etc. You can't do that when you have a monster like Kron able to suck up a guillotine out of the slightest mistake.
Wrestling is about aggression. Hesitance ruins good wrestling.
The most effective wrestling in BJJ at the elite levels would be Marcelo's in my opinion. He has honed in on a very simple and very consistent takedown for himself. Armdrag to the single leg. There's no first shot, second shot, level change, fake etc. It's simple and consistent.
That's what I see at least. And it's what I feel from attempting wrestling other BJJ guys as I wrestled for 8 or so years before BJJ and now use practically none of it. I use to think these guys are terrible at wrestling, now I just think the key elements to good wrestling are just too dangerous to use in BJJ.