Ok, I am not really sure what to think regarding Twilicorn.
On one hand, I feel that it can genuinely disrupt a lot that the show has built up. First, It interrupts the equality of the mane 6 because it is obvious that Twilight is now more special than any of her friends. Second, Since they're going to make a season 4, it seems out of place. I half expected Twilight to eventually become an alicorn, but only at the very end of the show. This is because by becoming a princess, it implies that she has learned everything that is needed to be know about the magic of friendship (at least in my opinion). And if that is the case, why continue the show. It kind of robs closure to the story. Last, What happens to all the other characters of the main 6? Since Twilight is now a princess, wouldn't that mean that she needs to go someplace far off to rule. I think ponies maintain the tradition of loyalty being aloof from commoners, which goes against all the values being built up.
I can only find a couple ways of this working out.
One being Firelord Derpy's Idea
I remember seeing this idea somewhere but can't find the exact location/ Plus i've modified it a bit to make a bit more sense (at least to me)
The basic premise was this: In one of the premiere episodes Twilight becomes greedy with the power of being an alicorn (unlikely I know), when a powerfull evil starts taking over ponyville. Only Twilight isn't there to help stop and the other ponies in the Mane 6 need her help. Over the course of the episode, it will become apparent that in order to save ponyville and her friends, Twilight would need to give up her wings in some attempt to stop the evil from spreading. Thus returning her to her normal form and giving her an even deeper meaning of friendship like being willing to sacrifice something you like to help your friends.
The only problem is that there is still the spell in the book at the beginning and end of the episode. All it would take is for Twilight to utter the complete version of the spell and become an alicorn again (A fact that I think most people over look). Please correct me if I am wrong on that point.
Ok, so the pro Twilicorn side.
First, after all this is a show primarily for little girls. And as prevalent as the brony fan base is, they still come second to the original audience. And with the original audience being girls. Twilight's transformation into a princess reflects the dreams of thousands of girls. In essence they were trying to say "you can be a princess" without truly considering how hard it could be to continue the show after the transformation.
Further more it IS possible for the Mane 6 to stay together with a scenery change albeit with a few problems.
Look at dekutree64's theory
Overall, I think the last episode of season 3 was a bit rushed, and unfortunately I think it led to some decisions that may not have been completely thought out. And really, there is not much the fanbase can do to change what has already been aired across hundreds of thousands of t.v.s across America. And that it is just a better idea to trust in the writers to continue making the brilliant show that caused the brony phenomena
tl;dr
Both sides of the debate have merit (read the post if you want to know a few).
And there is not much that we can do to change it anyways, just rely on the writers to make it good.
I sincerely hope that I did a good job putting this thread together and that it will be understood for what it is.
Thanks,
The Pulse
Wow... 2783 Characters.