Perhaps, but surely you can agree that her constant presence affected his game negatively.
Not at all - her presence has hardly been constant since she's spent the vast majority of her time on initiatives for Scottish tennis and is now the GB Fed Cup Captain. Her presence, such as it has been, has been familial support and I don't see why that should be a negative impact. People have tended to harp on about the Judy Murray angle and make far more of it than exists, in my opinion. Ultimately he is responsible for his own game and such things that Lendl can bring to the table are likely to be minor and attitudinal but all ultimately stem from the player himself being willing to listen and put his trust in someone else.