Quite possibly and Walker is probably a better header of the ball and is no doubt quicker than TAA as well but its meaningless when you look at the whole package and what each player brings to their team. TAA is as fundamental to the way they play as the likes of Salah and Mane.
People on here laud Walker not because of his football ability (he has none) but because he is fast. In some situations his pace is an asset, I have no arguments there but he spends a lot of time on the ball and does nothing with it. In addition, he has an absolute brain-fart in him that can appear at any moment, so this idea that Walker is rock-solid at the back and is a huge asset to us is just pure fantasy.
I don't have the facts and figures but I expect that he and Mendy have similar stats when it comes to mistakes that lead to an opposition goal. One is talked about on here as being the best in his position in the WORLD (laughable) and the other is ridiculed and being hounded out of the club. I am not defending Mendy but when I watch our games, I see two full backs who make mistakes, are average defenders and both absolute dump on the ball. The only major difference I see, is one has had terrible injuries and is no longer mobile and the other has been somewhat luckier in the injury department.
Both need to be replaced.