Even so, it would be City level at best, or Large City Level, as displayed from Inverse Tohka's potential. I don't think that he improved that much, due to Shido's inability to handle most Spirit powers. He's not highly skilled, like Archer from Fate/Stay Night, whom he is the future incarnation of Shirou Emiya, who can handle their powers to their highest potential. Shido's not going to be like that. He's going to be: Oh, weapon. Sweat. He's not going to look for improvement, and he's going to rely on the same tactics over and over, no improvement.