I would agree with that, and I'd be willing to bet had there just been the NZ weather issue (your flight Berlin) or the QF7 issue, it would have worked out more or less OK (as much as these things can be when hundreds of people are involved) .. seems like a perfect storm hit (no pun intended) though.. and where do the staff magically come from? It would take time to find off duty staff willing to come in to assist, and if they pulled from, say, domestic that would affect things there. You can't just have staff paid to sit around on the off chance there will be issues either.
Is it good enough there was just one staff member at that desk? No, of course not. Was it handled poorly by the lounge? Hard to say if they were instructed to send people to the gate it's probably not their fault. Did the gate staff handle it well? Probably not, but again sorting out ~150 pax is going to take time, let alone those with more complex requirements.
I'm not trying to be a QF apologist by any mrans here. I am just trying to be realistic at the logistical nightmare that would have been going on that afternoon/evening. I am sure some hard calls were made in the operations area re resources and where best to use them.
I've flown QF a *lot* over the past 5-6 years and I've personally been involved with 1 delay over a few hours (the BNE flight) and a few minor ones (one was a 380 issue at the gate in MEL that had us sitting around for 90 or so min, though I was in F so it was rather acceptable

) but really overall operationally QF (like most majors) runs a pretty good ship *overall*
the sad thing is we always will remember the shockers and the fails in service and recovery. That's human nature and quite normal
and as a consequence we then have the choice to vote with our future spend.....