I can't talk to the J or F comments as I rarely, if ever get to travel in those classes... so, my comments are those that I have personal experience of. I'm also assuming you are talking about QF.
- I've never ever had to claim bags in Sydney and make my own way to international check-in by train. Bags are always checked from departure point and then just jump on the transfer bus from QF domestic to international. So, don't know what this point is about.
- I've only had two instances in the last decade of making a booking or change through service centre that could not be completed online and in both cases, the fees were waived when I asked them to waive it.
- Again, not my experience. I am a Silver now and I've taken 17 flights in the last 2 months domestically. I got exit row seating in 15 of those 17 flights. The other two times I managed to snag Row 4. Granted, all of my flights are booked only 2-3 days in advance, so I might be within the 60 hour timeframe for seat selection.
I do agree with the points on inconsistent staff and terrible on-board food (when it is actually something other than a snack pack, which is even worse).