T-tail
The problem with the 727 that was not understood initially was the deep stall.
The T design of the horizontal stabilizer elevator allowed the wing to blank the tail when the airplane was allowed to get too slow in a nose high attitude.
The drag of 40 degrees of flap could slow a 727 pretty rapidly unless a lot of power was added at the same time as the flaps were lowered.
The airflow to the aft mounted engines was also disrupted. With the elevator or even a stabilator in this condition (nose high and slow) and no air getting to the engines, the aircraft was uncontrollable. It was stuck in a stalled or near stalled condition.
This was new territory in this second generation jet, and several were lost before the problem was figured out. Flap limits and higher minimum airspeeds took care of the problems, and as long as the new limitations were adhered to, the aircraft was safe.
As for the difference in landing performance between the -100 and the -200, it had to do with main gear position in relation to the CG. when flaring the longer -200, the main gear could be slammed into the runway as the nose came up. Hence the slight pitchdown or relaxation of back pressure on the control wheel just before touchdown that savvy pilots learned.
We don't see designers opting for T tails these days.