The thing about that argument was that they were both right. Better tactics and better personnel can equally make a difference.
The truly great defenders are the best for many reasons, one of which being their superior instincts. Wenger needs more players -mainly in the center of midfield and at the back- who can take it upon themselves to be organized and disciplined.
It’s certainly never going to come from Wenger so any time I see us linked with an experienced, disciplined and talented player, I always feel it’s something that will take us forward. Perhaps not as far forward as it would under better management but at the same time any progress is better than none.