Transfers would be unsustainable once newgens become prominent (4-5 years in.), which is the exact time I would argue the AI begins to struggle against the human. Hopefully the new AI squad building resolves these issues.
SI could certainly look at the tactical meta and adapt the AI in updates. I think that would add some challenge but then you run into the danger of every team in the league playing 4-2-3-1 gegenpress. I would love to see tactical trends implemented into football manager though. Fluid Counter becomes the popular style, and then other teams adapt to compensate, then as a result gegenpress becomes more popular, or the 4-4-2, and so on.