with all due respect to Mclaren my own experience of design teams is not very fruitful if the head of the gang is not understanding himself as a host/moderator but is a strong personality and someone who really has a vision on how the finished product should look/behave.Maybe I did not have the pleasure to work in groups with above average people but it always tended to be something of a fight for the minimum in common and not the maximum that could be achieved...it was characterised by the etos everyone does his own work and does not care about the whole.I could be very wrong here ,but I feel a F1car design needs a strong single person to do the concept(maybe a team of two)but having that group approach is not leading to outstanding endproducts.
On the other hand Mclaren has now for some time produced differnt -not mainstream- cars so it seems they either have some VERY strong personalities in these groups getting their way -inspite of numbers not stacking up in reality- or they have absolutely no feeling for what is needed to produce the top car but the sheer ability and recources to extract the maximum out of the dog they concepted...