As someone who knows a bit about math, all these Fractals just having +1/+1 counters on them makes me cringe a bit.
It would have been better if fractals were only allowed in a geometric progression 1/1, 2/2, 4/4, 8/8, 16/16. But they all possess the same basic characteristics (green and blue vanilla critter). Considering the amount of leniency we give our other forms of entertainment, (ask anyone who has worked in a lab about how well the CSI new york team does PCR, how well the doctors diagnose on Grey's anatomy) I think the term is just fine.
Fractals don't just repeat infinitely inward, but outward as well. Unless Wizards wants to make an entire plane that is just one fractal, some creative liberties are neccessary. The way the planeswalker's guide describes them, it seems they can exist simultaneously at different sizes and scale up and down easily. Having their size always be variable upon creation seems like a good enough way to represent that without being too complex for a token.