I disagree to some extent. I really do think that Jorginho was really good in Serie A and I doubt he just lost it. I think it's quite often we see good players from Serie A turn into shit when they join any EPL side due to a huge difference in leagues. I think it's a risky move (which isn't really, bar big WC stars) but he might as well pay off. If we get his old form back he's way ahead of our mid players imo. But even at this point I wouldn't say he'd weaken our mid, that's quite harsh, especially considering how shit our mid is.
But I'll give you this. Of course, there are better options than Jorginho (I mean players, not available players per se) and it's not like Jorginho is a huge move, but it's still quite decent if we're getting him for giving Berna. I doubt many clubs would take Berna with their arms wide open, not after this season surely. And it's a question if he'd accept warming bench in some other club. If anything I'd try to use him to get Zaniolo.