The advantage of Mode 1 is that it makes manoevres like rolling harriers, rolling circles or any rolling manoevre easier to learn because the primary controls are linked to one stick; rudder and elevator.

MOde 2 pilots who can pull of these manoevre are much more skillful pilots and probably missed their calling as lead guitarist for a major band somewhere. Why more skillful? Because the primary controls for the rolling manoevres are decoupled and it requires far superior left hand right  hand co-ordination.

For right handed people decoupled mode 2 is preferable. For left handed people, decoupled Mode 3 is preferable.

If you prefer the controls for rolling coupled then Mode 4 is actually easier for right handed people and mode 1 easier for left handed people.
So for the majority of people Mode 1 is essentially 2 wrongs.