Unfortunately, this is a misfortune that was inevitable from the start. Much like modern manga artwork, the vast majority of ponies share the exact same base. Speed Racer, Gigantor, Kimba. These did not have this problem. Old ponies didn't, either, because we only focused on a small group of them. There was never a big crowd of them like there is with FiM. Use dozens or hundreds, and you will see repeats. Use less than a dozen regulars, you have individuality. Firefly, Surprise, WW, Fizz, Gust, Buttons, Bright Eyes, Baby Lickety Split.