League of Legends (LoL) Question: Why is Leblanc so popular now?

It isn't champion herself that has changed, it's the environment around that has helped. That's simply the nature of League of Legends. When one thing falls, the next best thing takes its place. For example, Kha'Zix was strong, but then was nerfed, which led to Lee Sin, Elise and Evelynn to be strong. Those three were nerfed, and suddenly Kha'Zix and Rengar became top picks, alongside Lee Sin.

LeBlanc's period of dominance came after Kassadin's period of strength. When the silence was removed, they went to the next best thing, LeBlanc. LeBlanc was popular because of how little counterplay there was to her combo due to the silence. Little counterplay means reliability. You saw that when Sigil of Silence turned into Sigil of Malice and lost the silence, she dropped off the face of the planet. Due to the surge of assassins, such as LeBlanc, support mages became popular, and then assassins made their resurgence. Except, which assassin was it that made the biggest resurgence? Talon, yet another champion with very little counterplay due to the silence. Alas, the silence from Talon was removed, and... Oh ****, there's no more assassins with a silence.

After patches of thumb twiddling and re-evaluation of life and our existence within League of Legends, Zed made his resurgence as the premier assassin. He was the next best thing. Zed had ridiculously good burst, yet was still able to get out of harms way after he performed his combo. People then realised, "Wait, isn't there another champion that can do that?" Yes. And then came the resurgence of LeBlanc, who was not only able to have the same play and assassination potential as Zed, but was in fact safer than Zed with the fact that she is ranged and has more mobility and crowd control than Zed.

TL;DR When the environment changes, the next best thing takes the place of what was once the best. LeBlanc just so happened to be the next best, and that's why she is popular again.

In my opinion, it's because people have learned to play her without the silence. When they took away her silence, they didn't touch her damage. She could still deal the same amount of damge as she could before the nerf came.

People said it killed her, but I highly disagree. It simply gave her a higher skill cap. She has to be far more decisive now in who she blows up, instead of the first person she sees. Plus, they even buffed her not too long ago. They gave you more time to teleport back to your original spot with W, and I believe they buffed her Q.

Could be the mr nerfs, or just that some pros played her.

I haven't seen an increase in her picks.

In fact, LeBlanc's W's manacost was reduced in 4.13. Okay it was small buff but 4.17 was huge buff and everyone started playing it after that patch. Basically the time to reactivate your jump was increased from 3 -> 4 seconds and passive got huge buff. It always had a lots of damage but now he is almost impossible to catch if played well.

Cause of it's great juking potential it's also great soloqueue-carry. My friend is dia 1 and at the moment LeBlanc is pretty much only champ he can carry with in this pretty ******ed soloqueue. Katarina, Zed, Syndra and Akali are also pretty hated enemies at the moment. CC-based team-comps with one hyper-carry are really strong. So A) it has got huge buffs lately and B) it also fits most team-comps.