I used to think the door in J is hokey and ineffective.

but after several flights in BA J I have come to really like and appreciate it. It does increase privacy and makes it less likely that two persons passing each other in the aisle step into my space. I do sleep better and rest better with a door. So I find I rate my flight better with a door than without.

As to the quality of flight attendants, I believe that JetBlue is on the right track. JetBlue trains, a cadre of specialized mint class flight attendants. They are paid more and must undergo special selection tests and special training. They take special pride in their work. Singapore Airlines also especially selects its premium class flight attendants.