Here are some routes: London - Sydney, Sydney - Los Angeles, London - Tokyo, London - New York, New York - Tokyo (in fact Tokyo to just about anywhere), Singapore - London. It'll be mainly ultra-long haul stuff where the actual frequency isn't important, the only reason there are three Qantas 747s a day to LA is cos you can't fit 1200 people in one. It's such a long flight that it doesn't matter to the customers what time it arrives, they're not going to be doing anything for 24 hours after arrival anyway. Same with London - Sydney (2 BA 747s, 2 QF 747s), all four flights are practically flying in formation, all arriving at Heathrow within two hours. BA can use the uplift on some routes even if they are slightly reducing capacity on others. Thing is that the economics of operating one of these things competely rammed with economy seats will be so amazing that there may be radical changes to the whole air transport map as low-cost carriers offer fares on high-density low-yield routes such as New York - San Juan, New York - LA, trans-Atlantic (Oakland or Newark - London Stansted for instance) at third of the current fares (and make a huge profit).
It'll make a great freighter, but as with the 747, industry observers will expect it to become mainly a freighter once the new SSTs kick in. It'll fly really empty for the first few years of service with bars, bedrooms and a gym, poor loads maybe compounded by a heavy worldwide recession that I expect in the first five years of the next century (as was the case in the early to mid 70s as the 747-100s came along). The SST will never materialise and the air travel market will adjust to the new scale of the A3XX, coinciding with a recovery of the world economic situation, and the aircraft will be as revolutionary as the 747 and be the perfect size for the market by 2008 and sell more than 1,000. If it has The Airbus Cockpit then Boeing-centric airlines like BA can still have commonality with it's A320 crews, and still keeping the 747s and 777s which won't be the flagships anymore, just footsoldiers like McDD often were in mixed fleets before the merger.
By the way, the bars, gym and smoking lounge will be history as soon as the loads pick up. Many airlines couldn't fill the 747s in the 70s and American Airlines actually had all of Zone E as the coach class lounge, with an aluminium piano and everything. When the loads were better, that thing was ripped out faster than you can say "Play it again sam". The same will happen with the A3XX. Just cos a plane is bigger doesn't make it more luxurious.
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz