I choose none. Here is why:

Rainbow Dash: Would it look like she would turn away from her friends during a major problem? Would she really become a traitor and be cast into Cocytus? She would never ditch her loved ones.

Twilight Sparkle: Of course she has the Magic Element because she has proved time and time again to help out all she can for good.

Rarity: She has a heart of gold. Despite what she may have done in the past, she is still a caring pony.

Applejack: Yes, it's true that she may have lied, but she was very reluctant to do so. She hates to tell lies.

Fluttershy: Who would say she's not a kind and caring pony? She may be cowardly, but that is not the issue here. She is caring, even though it's usually to her animal friends.

Pinkie Pie: She spreads joy and happiness to her neighbors and peers. You'd be wrong to say she doesn't deserve her Element.

it was hard beetween Dash and applejack, they do have good features, but dash is only loyal until last minute and applejack is to my point of view the least honest of the mane

I think rainbow dash should had been courage and applejack loyalty

Rarity for sure.

I guess I should go through tests to make sure of who least fits their element.

How often do they show it?: AJ doesn't really show her element that often but it isn't usually a big deal since how little we get to focus on her ,Same can be said for Rarity, Twilight does show it a pretty good amount, Fluttershy shows it to the point when it gets annoying, Pinkie also shows her element when it is needed but sometimes it can get really annoying, I have to agree on lililc on this one at the last minute is the only time when she shows it.

Do they ever go against their element by showing the opposite trait?:Rarity does go against her element quiet a few times. And so does the others but, At the end when it really counts they do show it when it's important to and sometimes when it just gets strait out annoying.But, they do go a against their element sometimes. Flutter,Twi and Pinkie barely ever go against their element I can probably only think of 1 or 2 times when they did, AJ tells half truths, And RD constantly goes against it by running off when it is needed, Rarity also goes against her element a lot but she does show it sometimes and when they do have her show it, it gets pretty annoying pretty fast. It goes to a point when she is showing way too much of it.

Did they show it good enough when they did?: Again Twi,Pinkie and Flutter are all safe, Rarity I'll also give a marshmallow to since at a lot of different view points she can be generous and when she's she does show it pretty well again sometimes to the point when it gets annoying, RD is okay too since she shows it when it is important, Same can be said for AJ.

end results: I can't decided against RD or AJ. I think RD should win since AJ mostly went to the half lies route .

Hmm, I wonder who chose Twilight.

twi sucks her element was handed to her