Iron Stylus has gone on length on what he and the relaunch team would like to do to Sivir when she undergoes her visual rework.
And honestly? It's all awesome sounding.
It's always been hinted at (through Sivir's old and current lores, as well as the original ideas for her skins) that Sivir isn't like most of the women portrayed in League of Legends or other games, being that she's tall, she's strong, and she's very hard to fight against on her own. Down to using 'strange magic' to change the flow of battle in her favor she portrays the 'Amazonian' trope quite well in all her incarnations, and all of that will be remaining once the visual upgrade comes to pass.
I guess I just wanted to relay that, as a Sivir player.
Iron Stylus has said more on the subject! (Thanks Jao and Jom for the insight).
Here he talks about redoing Sivir's origin story and how delicate of a process that may be, which he's not wrong about. Personally I like that Sivir is one of the few in the League that has no alliegence and has no qualms biting the hand of her old master(s)(which is Noxus. She's a Noxian who does not serve Noxus. How nutty is that?). She's not like Garen or Katarina who blissfully follow their higher ups orders, but she's not crazy independent either. But if that gets skewed slightly I wouldn't be too broken up since, hey...a lore update when they're doing all this lore stuff does sound nice.
He also talked about her attire and how that might change entirely, a bit like how Karma's attire got changed to better suit the character (and was the only good thing about that particular rework), which is good. If Ironstylus can find a nice niche between armorkinis and something actually practical, all the more awesome.