Its the second match of the manager's second season. Its an odd time to suddenly throw a new system at the players based on 1 signing (who is now injured anyway). Especially when said signing is being asked to play a role he literally never played at his former club and has shown little to no evidence he is suited to.
Its firmly under the category of "completely bonkers" until proven otherwise, which I highly suspect it wont be.
How do you know it will come? 45 minutes of looking just about ok and 135 of looking a complete and utter shambles might not be enough to fully condemn something as a crazy idea, but its certainly not enough to indicate it isn't crazy.
I would feel a lot more comfortable if we still had Fred and didn't have Mount, and that's nothing against Mount, but he very obviously doesn't pay the same position as Fred, and we needed Fred 56 times last season. There were very few games we were crying out for a second no10...but we did need to emergency loan another midfielder when Eriksen got injured.