Wider aisles means easier egress in an emergency situation???? Not really. Mos aisles in E/C are between 17 and 20", its not going to make a heck of a lot of difference when the requirement is to evacuate a plane within 90 seconds.
The FAA stipulates that at a height of 25" and below the aislewidth must be 15" wide. Above 25" the aisle with must be 20". These are the only requirements airlines must follow.
Wider aisles are obviously preferred because you won't have galley carts beating up the seats, especially when you are trying to get some shut eye. Also, F/A's would prefer wider aisles because it would allow better ergonomic function when servicing the pax.
As for F/As not likeing 2-5-2 because of servicing? Well I find that interesting since on a 2-5-2 config you only have to reach over 2 seats to serve the middle seat once per row, while on a 3-3-3, you have to do that twice per row.
Within the same size fueselage, 2-5-2 offers no more pax width room over 3-3-3 unless you shrink the aisles.
Delta has one aircraft going through 3-3-3 reconfig. Thats not due for service until mid-january. Pilots don't get much say in cabin configuration unless it regards crew rest facilities. (maybe they do have a say at United). I'm sure the pilots are enjoying the mock-up of the overhead crew rest, who wouldn't. Its there own private condo in the sky