Putting the tailplane on top of the fin makes no sense other than to the marketing department who, back in the '70s, probably though it looked cool. It means you need a beefier fin to take the loads, which adds to the weight - at the extremity of the aeroplane, which is just where you don't want it. Hence PA38s have a short fuselage (to limit the effect of all that weight at the back) and are therefor directionaly challenged in all but the calmest air - they wag their tails.
Also, the elevator is above the prop thrust line so back stick won't raise the nosewheel off the ground at low speeds (very bad news at rough fields). Then, at a realtively hign airspeed, the elevator starts to work in pure slipstream effect, the tail comes down, the elevator enters propsteam effect, and it over-rotates for the pilot input.
Having said that, I like the aeroplane. Once in the air, it handles quite well (tail wagging apart, but then my beloved Chipmunk is not totally immune from that). Far better ailerons than the C152 (but the 152 has those lovely flaps!), and more room in the cabin.
If it had a conventional tail, it'd be a great little aeroplane. The engineers won, despite the influence of the marketing guys.
SSD