If you're going to update Syndra's lore...
Please build upon her current lore and personality, don't just completely rewrite her or anything.
The way I've seen Syndra; is that she was born with immense power and capability to achieve greatness with her magical powers, but because Ionia (or Karma) feared her power as destructive, they sent her off to be homeschooled all her life in order to limit her powers, causing her to kill her master and live in solitude. She now resides as a super naive teenage girl with the power to blow up the universe.
I want to see more of this, such as how she felt after realizing how much everyone fears her power, and a build up on her "power hungry teenage girl" personality.