RE: Do we still need trainer aircraft??
The semi-symmetrical winged Avistar and others like it are an excellent trainer/basic aerobatics plane, with an instructor. Put an O.S. .46 ABC in it, and it will scream if need be. At least it will fly inverted a bit with the wing.
Flat-bottomed wing trainers usually get put aside quickly after solo and a few rounds of the circuit.
Trainers? Always!
Charles