Putting the tail "high" - as a "T" rather than "+" configuration - has the advantage that it:
(1) moves the tail further aft, assuming a swept fin - better tail arm, so smaller tail is possible
(2) moves the tail out of the way of the rudder, allowing a single rudder along the span of the fin, rather than needing it to be split.
(3) increases fin effectiveness by adding an endplate effect to the fin
Conversely, the higher tail usually creates more load on the fin structure.
The loading issues that are referred to above are not due to the aft-mounted engines - there's no reason why that configuration should be more or less easy to keep control of the cg. I suspect that the problems arose due to the way in which the aircraft was developed/stretched over the years, with the design gradually getting less-optimised in terms of weight and balance.