Well I've never had cause to interact with ground crew much at QF but I have always been served promptly and with a smile when asking for seat changes or anything else even as a lifetime NB.
Maybe I've asked at the wrong time/place - I've learnt that asking for a nice seat (note - not asking for a freebie upgrade or even an ODU, I'm not that silly) at the either the MEL or BNE QP service desk is a good way to get your head bitten off.
Unlike at DJ where I was at the desk at the gate to enquire about a seat change and then ignored while the attendant turned around, walked away to be in view of the aircraft (this was in ADL) and make obscene sexual gestures to the baggage crew down below...that experience has put me off ever booking another DJ flight.
I can certainly understand why - that's completely unacceptable behaviour by anyone in any part of the service industry. Did you speak to a supervisor or provide feedback re. this?