Many people will focus on seat arrangement at a reduced pitch, round seat, and how much it is to board. But, a problem I came up with is that "Is it possible to stow all of the belongings into overhead cabins" Even if there are more seats on the aircraft, the room for baggage storage is still the same. It means it's much more difficult to bring baggage into cabin. So, weight limit for free baggage will be lowered from 10kg to 5 or 7kg. Backpackers will have to pay attention to their belongings.