On a wing the line joining the leading and trailing edges is called the chord line. At typical approach speeds the angle of attack (between chord line and airflow) will be in the region of 10 degrees.
On propliners and the early jetliners the only high-lift devices were the trailing edge flaps. So on a typical (three degree) approach the pitch attitude was quite low due to the chord line orientation with flaps lowered.
Later jets had leading edge slats, again changing the chord line orientation, resulting in higher pitch attitudes to attain the same approach path.
So the pitch change during the flare for landing was greater for slatless aircraft in order to achieve mainwheel touchdown before nosewheel. The Strat required an even greater change due to the gear geometry, which perhaps accounted for 'wheelbarrow' landings being more prevalent on this type.
Why did the Strat (and precursor B-29) sit nose up on the ground? Was the intention to ensure adequate prop ground clearance?