KLM has this very favorable layout in its retiring MD-11. Its replacement, the 777 (with a similarly wide fuselage), is being fitted with the standard 3-3-3 layout.

Based on the following:
- happy = aisle with one person inboard of aisle, or window one seat away from aisle
- neutral: aisle with two people inboard of aisle, or window two seats away from aisle
- unhappy: middle seat one seat away from aisle
- very unhappy: middle seat two seats away from aisle

The possibilities are:
- 2-5-2: 6 happy, 2 unhappy, 1 very unhappy

- 3-3-3: 2 happy, 4 neutral, 3 unhappy

- 2-4-3: 4 happy, 2 neutral, 3 unhappy


It seems to me the 3-3-3 layout is easily the worst.

With 2-5-2 airlines can at least accommodate their elites in the favored '2' clusters.

With 2-4-3, airlines would have the flexibility of accommodating groups of 2, 3, and 4 travelers, and minimizing the number of disgruntled travelers.


Is there any particular reason airlines are shunning this 2-4-3 arrangement? Structural? Love of symmetry?