I know this post will get downvoted to hell by people who can't be bothered to even try to counter LeBlanc, but I am of the firm opinion that these nerfs must not go through. They are absolutely insane and it is inexcusable to nerf any champion into uselessness like this, without any meaningful compensation. Here are some of my thoughts on LeBlanc's current state, as a LeBlanc main with over 500k mastery points.
I do not deny she is too strong right now, I do agree. But I do not agree that her W is the spell that should receive any nerfs at all - it is a high risk, high reward ability. It puts a squishy mage in melee range for at least 0.25s, which is more than enough to lock her down, believe me. Distortion is a risky ability to use, and should therefore remain as powerful as it is currently. These nerfs are insane and I have no idea what Riot's balance team is smoking. Its mana cost is already astronomical, her W needs no changes at all.
The culprit here is her E, her chains. Ethereal Chains is a very low risk, and pretty high reward ability. It has pretty long initial range, and a crazy huge tether range, which is what most people seem to complain about, and I can see why. But perhaps instead of outright nerfing the tether range, which is what I assume most people would want to see, I think a more interesting take on this issue is to give LeBlanc a delay between dashing into someone and throwing the chains. Currently it is extremely difficult to dodge her E if LeBlanc dashes straight onto you, and since she's now attached the chain while directly on top of you; 1000 range is a lot of distance to cover in 1.5s and very few champions can create this much distance this quickly, especially given that LeBlanc has another dash up her sleeve to keep up with her target if they try to run away.
Another possible and quite reasonable nerf would be to increase the mana cost on her E, as 40 mana for such a powerful ability is quite rightly ridiculous. But not more ridiculous than the current PBE nerfs, for which I simply cannot find a strong enough word to ridicule them with. Whoever is responsible for them should seriously think about what they are doing, and perhaps rethink their membership in the balance team altogether. I know the balance team is a bunch of AD assassin fanboys, with the lethality buffs, Edge of Night etc, but come on guys.
Seriously though, if these nerfs go through, she will probably drop 3-4% in winrate, which is a massive drop for any champion. She already stands at 47.7% winrate as of writing this post, which is not in my opinion indicative of a big issue with the champion. Is she difficult to counter? Yes. Is she annoying? Yes. Is she broken? No.
For God's sake, come on people, the new LeBlanc plays exactly like the old one, except the new LB has a few more tools, but fundamentally both iterations are practically the same. If she doesn't get fed, she doesn't do anything aside from an occasional snare here and there, but damage-wise she is a cannon minion. It is so simple to counter her it's just stupid how... uh... well, stupid people are.
Here is how you beat LeBlanc:
1) Buy MR. Lots of it. Doesn't matter if your own damage suffers, you must prevent her from snowballing at any cost. Merc Treads, Abyssal and possibly RoA is absolutely more than enough to make it impossible for her to kill you 1v1, and that is what you need to achieve.
2) Spam pings when she goes missing. Ward the small bush in the river and always be on the lookout if she doesn't show up in lane. If you see her leave lane, or even suspect it, spam both side lanes with pings until they retreat. Again, it doesn't matter if they lose a few minions because of this, not letting LeBlanc snowball is far more important.
3) Never walk alone. Fairly simple, no explanation here.
4) Group early, take objectives and win. LeBlanc's teamfight presence is very poor. Nonetheless be careful, as she can double-dash into your team if you group too tight, and then bounce her Q around you to deal massive damage. Be on the lookout for flanks and focus her down as soon as possible if she tries this.
I've said it time and time again but I will say it again. These nerfs are absolutely insane, just like the maniac who came up with them in the first place. THEY. MUST. NOT. GO. THROUGH. For Christ's sake, use your brains a little bit, rather than just gut numbers like this.