I don't have a problem with the boarding time of passengers. In real life on an A320, boarding will commence approx. 30 to 45 minutes before scheduled departure time and from my experience practically all this time is used to get a full A320's passengers on board and settled.
There are two ways to shorten boarding time. Either increase the speed of boarding in the GSX settings, which tends to look unrealistic, or after you press 4 for boarding on the coutl menu and a green bar with suggested numbers pops up, in my case it is usually 155, reduce the number of passengers to whatever meets your time requirements. Obviously, fewer passengers board faster. Six crew (2 flight deck plus 4 cabin crew) plus 150 passengers take approx. 10 minutes to board. Six crew plus 22 passengers board in about 4 minutes.
I hope my original post re the boarding sequence of the flight crew is still on the future updates list!