Inconsistency.
The surliness of the older staff. Its un-PC but I said it and it's true. IMHO there should be a case of forced retirement at age 35+ EK-style.
The fact that BA is riding on its old reputation to offer substandard service.
The only reason I use BA is because I am UK based and prefer direct flights. I would love it if EK set up shop in Heathrow and ran BA into the ground.