Originally Posted by
BoeingBoy
That primarily due to the smaller fuselage diameter. To put the windows at a good height for the average sized adult they would be above the point where the fuselage is curving back inward, making it hard to look down.
Regardless of why it was done in the first place, Bombardier all but admits the placement of windows on the CRJ-100/200 was a mistake when you consider one of the advancements they touted with the -700/-900 was improved window position with the windows placed higher.