Well this is an opinion that I've been developing for a while.
The thing is, he was brought into Ferrari as a consultant, and although he stayed with the team for a number of years, their lack of success during this time couldn't really be seen as a glowing indictment of his ability.
Then Jaguar hired Bobby Rahal, who was all set to be really successful. His style was to bring together the disparate elements of the team, and encourage them to work together, rather than to try and be better than their colleagues. This is a successful strategy, as it has worked in many other teams in the past, and I think you'll see Dave Richards do this at BAR over the coming 12 - 18 months.
But then Lauda came in and discord rose, and Jaguar started to go backwards again. Lauda just creates conflict. He was even sacked from the board of his eponymous airline! Lauda has created nothing but strife, and he seems to have this devil-may-care attitude, and a real arrogance concerning his own abilities and leadership. It's like "It's my way or the highway matey", and that's not what's needed at the team at the moment.
Then he pipes up and says he's going to test the F1 car. Why? How often do you see any other team boss drive their team's cars? What possible good could come of it? At best it's just a disruptive distraction from the business of the day - namely making the new car competitive for the coming season - and at worst it puts team personnel in danger. And he hasn't even driven an F1 car for ten years, so what can he possibly gain?
He claims it's so he can better understand what the drivers are going through, but why does he need that kind of understanding? It must be to gain power in some area of the team management, and that's not the sort of power that a team boss needs. Again, I ask which of the other team owners drive their cars? The only one that comes close is Minardi boss Paul Stoddart, who does demonstration drives in the 2-seater Minardi on team away-days.
Lauda isn't what Jaguar need at the moment. There's too much of an ego there. I can't help but feel that he would sell the team down the river if it made him look better.