if she has a decision in the matter it's essentially a "canterlot or ponyville, them or me" situation.
again i just don't see the point in such a thing. it's not necessary when you've already got three alicorns and six ponies who control strong magical gemstones
what would be acceptable if it was an option to save the world (showing dream-like examples), and twilight is pressured into doing it, however in the end she makes the right choice
but there are no more two-part episodes this season so
Basically this.
Besides, why would it ever be an option to save the world?
Consider also that her link to her element of harmony is based entirely upon her connection to her friends. Remember that Magic requires that "spark" so to speak. So if she actually DID leave her friends, she would probably lose the power of the element too. Therefore, ditching them = bad idea.
There's an old proverb that goes
"Those who walk alone, die alone. Those who walk with friends, live with friends."