Depends on what you mean by 'Achieve the most'. Do you mean win olympic gold? a world title? land a triple axel? the most triple triples? set a personal best, surpass 200 points?
From seeing what the junior ladies have done so far, I can see the Adelina, Liza, Julia, and the two Polinas (but only one was offered here, and doesnt this line up remind you of the US senior ladies from 2008-9 a bit? all young and extremely talented but puberty holding them back?) all on the Sochi podium, but once again this is what they said about Mirai Nagasu/Caroline Zhang back in 2008, but by 2010 Caroline's technique and a growth spurt left her out of the top 10 at nationals BUT Mirai did come 4th at the olympics.
That being said, there are 3 US ladies listed here (though I believe that there are other US ladies that should have been included like Yasmin Siraj, Nina Jiang, Leah Kisner who could easier improve to medal contention at nationals in a year or two) and you can't forget Zijun Li who could rise like Yuna did from a country not known for ladies figure skating.
Overall, this question is far too open ended and its much too early within the 4 year gaps of the olympics to see what the up and coming skaters will be like. Unfortunately like Adelina already, some will have to face the issue of growth spurts, puberty, and mental stability.
But if I had to guess after writing this really long reply.... I'm going to say Liza, because from the withdrawal at this year's world juniors with plans for her 3A I could see her like a Mao Asada in 2014, and if being able to do extremely difficult jumps and medal at the olympics is considered achieving the most than well..