KingdomFantasyXIII said:
It actually is. I found polls that showed this:
http://www.novacrystallis.com/2013/01/japan-ranks-their-favorite-female-characters-from-the-final-fantasy-series/
http://www.siliconera.com/2014/01/06/final-fantasy-airborne-brigade-players-vote-yuna-popular-heroine/
She's always in some form of top 3 females in the Japan FInal Fantasy. It's surprising to some I know, but this is the same country that thinks Tidus is the 4th most popular and amazing male main character in the FF series (save for Zack, Cloud and Zidane).
Believe me, Japan thinks ind much different ways.
Actions (and money) speak louder than polls. Lightning's game sales tanked HARD. You could have many polls where she wins, because die-hard Lightning fans will vote for her over anyone else (and the vote is more split between all the other characters... Aerith or Tifa alone splits FF7's fanbase's vote), and she has the benefit of being shoved in your face more than any other FF character in recent memory (Terra and Celes could be considered much better, but they haven't received NEARLY the promotional push that Lightning has and Lightning is far more recent and plastered all over the covers). And then there's the fact one of the major polls was from their own webpage with only 500 votes split between 42 characters. That's an incredibly small sample size.
But, again, sales numbers. If Japan really loved her like Toriyama claims, then why was her game the lowest selling console Final Fantasy of all time, behind even junk like Dirge of Cerberus? Why was it outsold a week later by a port of a 13-year-old PS2 Final Fantasy game? Why did Bravely Default nearly match it in sales despite being on just one single portable system with a lower install base? Why did the FF13 series SHRINK by 85% following FF13's launch where most trilogy of games INCREASE as they get better and gain more players?
The Japanese love for Lightning is vastly overstated, and the circumstantial polls conducted don't match the actual sales don't support it. What I'm told is, mainly, she's fun to look at and cosplay, but even people in Japan don't actually love her character.