Should he be confirmed as expected this week, the former England international would, at least, be the perfect attack coach - and it would be difficult to find someone who could do the dual roles of attack and defence coach like Farrell does.
But Catt has only recently retired from the professional game and has played with as well as against most of the players who could be selected for England.
Also, as a coach at London Irish he has spent a copious amount of time studying and analysing these players. He knows all of their strengths and weaknesses - and who has international pedigree.
Catt can rejuvenate what is a pretty lacklustre England attack. Lancaster's team might have won four of their five Six Nations matches, but they lacked creativity and consistency.
There is more emphasis on defence than attack in the modern game, which is disappointing as defence does not require as much thought and technique. To be on the attack means you have the ball and are trying to drag defenders out of position; it involves bluff and subterfuge.
Now, a well-executed defence strategy can be just as intelligent - but you do not have the ball and only have to worry about your channel.
Looking at this season in the Aviva Premiership, a lot of the teams have preferred not to have the ball rather than play with it so it is hardly surprising that the art of attack is dying in England's top flight.
Catt was brilliant when he had the ball in hand - he loved to attack. But he will be up against it to work with players who focus more on what their opponents do rather than improving their own skills.
Catt has to get the England players passing the ball accurately and, more importantly, comfortably. A pass should be played perfectly so your team-mate does not have to break stride. An attacking style of play needs confidence; for players who have those natural attacking instincts this comes easily, but for others they must practise the drills repeatedly until they start dreaming about it.
The better players then add their imagination into the mix to create exciting and fluid rugby. Catt's job will be to encourage the players to use that imagination and not be afraid to make a mistake. If he can instil that belief then England will realise that attack is the best form of defence - and only then can Lancaster's men challenge the world's best.