There's no such thing as 'dead certain' on the next manager. Not unless you are getting Pep or Klopp, which we obviously aren't. Every other manager in the world has question marks over them in some shape or form. Obviously some have more question marks than others, but ETH has already answered many of those questions to the negative.
Out of our previous managers, LVG is the only one who has any kind of base to say that they might have done better with more time. He was the only one who actually set in place a system that might have led to success. Even then, it's highly unlikely that he himself would been able to do that, and we would have needed to sack him and bring in somebody else who played a more aggressive, attacking version of his football to start moving the right way. Instead we went pretty much as opposite to that as possible and wasted any potential good that came from his time here.
Moyes clearly wasn't taking us anywhere. Mourinho clearly wasn't. Ole clearly wasn't. And now ETH clearly isn't. All of them left almost nothing that the next manager can build on in our attempt to get back to the top. Dalot is virtually the only thing that ETH can point to in terms of coaching players the right way, and giving Mainoo and Garnacho a lot of games (too many to be honest) as well. Otherwise, there's nothing.