Such an old thread, but couldn't care less.
Now I'm not sure wether or not your saying if the show didn't exist at all if you mean Fim or a mlp cartoon in general considering I'm too lazy to comprehend large posts like those. But I'll assume the former since surely there still would have been a show
In my opinion, it probably wouldn't look and act like a dang anime with the gigantic eyes and plots, no pop culture references, and maybe something that isn't flash animated (seriously it's meant for internet animation) but instead hand drawn, well depending on the budget who's making it of course. For the characters they're personalities and designs would've been different because of how Lauren Faust and her team wanted to change and mix up the ponies for some reason. Examples of what would probably have happened is: Rainbow Dash would act like Rarity, Posey err I mean fluttershy would not have had wings, Spike would stayed blue.... Or pink I dunno. Lastly the writing.... I guess it depends really. And also it would be less likely for bronies to come along really, if there even IS a chance (I'm looking at you 4chan)