Challenges of Indian operations aside, there is a LOT of Australia to India traffic and Qantas is really missing out on serious revenue here, especially given the Jet Airways shutdown and the poor connections in HKG via Cathay (esp in the India to Australia direction). I would really think Qantas could do quite well by re-introducing SYD-BOM if they can hammer out an agreement with a local carrier for codeshare connections. The best-run domestic carrier by far at the moment is Indigo, but I as an LCC they may be quite resistant to codeshares.
Singapore Airlines opposites 5x return SYD-SIN flights on some days, and these are packed with Indian-bound travelers, both Indians returning home and Australian businesspeople. There is a huge market here, and Qantas should take on the challenge in my view.
I would also like to see a later morning departure from HKG that can pick up connections from Cathay's existing India flights, but I guess that is hard to schedule with the Sydney curfew. CX 139's departure at 8:40 is too early to connect with a number of arrivals from India, but given it's 20:50 arrival into SYD, I suppose they are reluctant to schedule that later to avoid curfew issues.