Flat out disagree the Pony is under modelled.
Based on its weight, engine power, and wing area, and high speed wing design <, it seems to be fine.
Also, as has been pointed out, and experienced by anybody who spends any time in the MA, it is clearly one of the most succesfull designs in Aces High. When flown to its stregths, its a very capable fighter.
Is is perfect? no, it is not. Neither are any of the other ENY5 1944 rides, they ALL have drawbacks. Its a machine, thats all, it does not possess supernatural qualities.