I'm not clear how preallocated seating works better for those with children as often when arriving at the airport there are only spare seats and middles left. Out of say London Heathrow, by the time check-in opens often many of the seats have gone already to inbound connecting passengers, or to the BAEC Golds.
However even with bus boarding (actually unknown for Easy in my experience; maybe different stations) a low sequence number will get you on the first bus. I don't think there's a bus about which can hold all 148 pax.
Sitting on the aisle and blocking the other two seats seems to be more a US problem with Southwest and their ilk. US first-in passengers generally prefer the aisle for choice, Europeans the window. Anyone know why ?