Sydney & Melbourne should both have excellent Qantas J lounges being Qantas 'home turf' but when you compare it to what Cathay offers at HKIA, Malaysian offers at KUL, Asiana offers at ICN and what EK offers in pretty much every one of their own branded lounges throughout the world, it's not all that hot.
I have not been in the MH or EK lounges, but that may change by the end of next year!
However I have been in both the - CX HKG J and OZ ICN J lounges, and find QF on par with CX when averaged out, and ahead of OZ.
I don’t drink wine very often, but accept your single item critique, especially since Qantas has decided that wine should be a primary point of difference with regards to its competitive marketing position.
However, the OZ J lounge at ICN is too small to cope during peaks, including wait times up to 2 hours for a shower, so check in early if you need one at the end of the day (before the QF code share back to Australia). The food options are absolutely minimal, and IMO only barely beat out airline lounges in the USA, and the layout and seating plan is very poor, unless you want to sit in rows of single seats, with poor accessibility, facing a TV (because obviously none of their customers do, which is why these seats are the last to fill up).
As for CX J lounges in HKG, they are nice, and given recent renovations they do offer improved ambience. However, The Cabin is just as likely to be standing room only, as a packed QF J lounge in SYD, and I find the food offerings are rather poor for my palete, when compared to the MEL/SYD Qantas International Business Lounges.
As for "home turf", I think that after the renovations in MEL T2 (when the J lounge expanded and acquired the old F lounge real estate) Qantas ended up with an enormously spacious lounge, and by creating sectional social areas, they have actually been able to give Melbourne the Network’s best J lounge layout. (In saying that, I agree that SYD T1 needs an expansion to deal with peak demand.)
So let’s take a stroll around the spacious MEL T2 Qantas International Business Lounge.
For a dungeon style lounge, IMO Qantas (in MEL T2) has created a vast and yet still intimate, welcoming experience (enhanced further by interaction with quality in-lounge staff) and is certainly one which I would rather enjoy over the OZ ICN J lounge, and on par with any of CX’s HKG J access lounges.
And as for QF T1 SYD J Lounge, I love this highlight