Just a few comments:
..... but they don't handle exceptions well. "No" is apparently the only answer they are allowed to give when anything goes wrong or is outside the rules...
Agreed! I had been flying with Airasia for over three years, and had no problems whatsoever. Although lately it's been one thing after another.
Had an issue purchasing an eGV (electronic gift voucher), so phoned their support line. I was given wrong advice. Email support has been the same. Don't even think about their web chat (you'll be waiting in queue for hours).
On one recent trip I was questioned by ground staff about visa (if I have a return ticket). I told him I have funds (and proof) to cover the duration of my stay. He got what looked like a manual and started reading it. Then after some more questions allowed me to board.
On the latest trip, I had a new passport, staff at check-in counter asked to see old passport then said go to immigration counter and have visa transferred. Immigration told me it was not necessary as the visa expired on that day. Come back to checkin counter and she tells me go back there and ask them to write on a piece of paper what they had said. When I asked her to write down what exatcly she wants from immigration. She closed the counter and came with me to immigration counter to confirm this.
On my return journey, I noticed one staff member checking smart phone boarding passes very suspiciously. She gawped in to the phones forever. I was hauled off the line due to the new passport not having the old visa. Supervisor was called and enquiries made for over 30 minutes. Afterwards, a group of three Airasia staff questioned me AGAIN!, about visa. Even some random general knowledge questions were hurled at me (I never realised this was one of the requirements to fly AirAsia). Never again, unless I hear/see some positive results/changes.