I can see four possible outcomes from this

1) Twilight becomes an alicorn; moves in with the princesses and the series end (with the fourth season already paid for and stuff this one is unlikly)

2) Twilight becomes an alicorn; moves in with the princesses and only has a minor part in the series. After which The series shifts to the point of view of a different pony; most likly Pinkie pie. (again I doubt it because the series centers so much on Twilight that I doubt they'd change the series so drastically.)

3) Twight becomes an alicorn but the alicorn form is only temporary and acts like a Sailor moon kinda power-up that she would be able to call upon. The following season would be Twilight training or something to become a full fledged alicorn.

4) Twilight become a alicorn but must learn master her new powers like flying. ( An ep featuring Rainbow dash trying to teach Twilight and Scootaloo would be a neat ep.)

I'm probanly wrong and none of these happen
we'll just have to wait and see.

5) Twilight become a alicorn then the rest of the series focuses on the cmc and struggles

Have a pleasent day

684174
I was thinking it might be close to the first one, but she turns it down when she discovers that it will put her apart from her friends. Whether she keeps the alicorn status or not in this situation depends on the nature of the transformation, I suppose. Maybe have a fighting destiny type of thing since it would make her unhappy.

Those ideas...they are just plain awesome...I love them...Daleks are not supposed to feel love.

684175 maybe sound like something the series would do

684177 thank you maybe one of them will happen maybe not (3 or 4 would be neat)

Rainbow Dash Presents: Flying With Twilight

684585 Now that would be funny

684174 i think she gives up the power to be with her friends

What if there was another outcome similar to the "temporary wings" idea. It could be an after effect of tapping, fully, into her elements power.

684623 most likely only time will tell

684696 aka a power-up she can call upon when shes in trouble

684174
I think she might become an alicorn but in some strange twist of events sacrifice her powers to save her friends then she'll learn some big lesson on friendship or something.
If I am correct and I might not be but she was revealed to be an alicorn with the episode that mixed up the cutie marks which caused some crazy trouble. So she might sacrifice her powers to fix it.
If I am not right then she will sacrifice them for another reason.

686660 that sounds about right. I kinda doubt she'll keep the alicorn powers at but theres no way to tell at this point

686793
True, I hope I am right I don't know what would happen if she stayed an alicorn