The Main deck cabin is appproximately 12 inches wider than that on a 747. The cabin will have the standard 3-4-3 747 layout, but Airbus have stated that during the initial design airlines asked for a cabin layout that would allow individual armrests for passengers. So that is where the extra 12 inches will go. (I suspect by the year 2020, it will be a 3-5-3 lay out.)
As far as standup bars are concerned, that is nothing new. All the original 747s had them - some airlines had two or three on board. Virgin and ANA have standup bars on their 747s and 777s respectively.
PanAm even had restaurant style seating on their 747 upper decks in the 1970s. The liability incurred by a standup bar is no more than that incurred by serving drinks to non-seatbelt wearing pax in their seats.
I suspect that the new A3XXs - at least with the premium carriers - will have a few personal first class cabinettes, a stand up bar or two for F/J class passengers - perhaps several self-serve drink/snack stations in Y class, a dedicated business center with internet connections for f/J class pax (ANA already has that), and a dedicated cabin for Y class pax travelling with small children and infants at the rear of the cabin (We can only hope !!!). Initially we may see an inch more seat pitch in Y class, simply because load factors may not be up to snuff in the early years of the A3XX's introduction. (I said MAY see, not WILL see). Of course, with SIA, etc, we will see improved PTVs, seat based internet connections, etc, but I'm sure that those will carry over to other aircraft.
SIA currently carry 20 cabin crew on their 747s (compared to BA's 14-16). I suspect that the number of cabin crew will increase to around 26 or so on the A3XX. I suspect that clever marketing will make it appear that self-serve drink/snack stations are a cool, new substitute for more cabin crew. At least it may give you a reason to get out of your seat.
And, oh yeah, don't forget that APU operated treadmill and the running track on each wing with swimming pool in the fuel tanks.
Atheism is Myth Understood.