A lot has happened to poor LeBlanc. A lot of very confusing things, in fact. My goal with this guide is not necessarily to tell you how to play LeBlanc, but to get my ideas, notions, and math out there so that we can figure out if she's still worth playing. On that happy note, let's discuss her abilities.
Sigil of Malice is her new passive. Now, there's are a few weird things about it. First, it takes 1.5 seconds to prepare its first time, but it has a 5 second cooldown per character. That is, you can only proc your passive every 6.5 seconds. This means that once you proc it the first time, if you can kill, do so as your passive is now useless to you.
Shatter Orb is your new Q. Allow me to be perfectly clear. It is almost completely useless for assassinations. At max level, it deals a mere 155 damage plus 50% AP. That's small potatoes. However, it can proc a large number of Sigil of Malices. When used in conjunction with Distortion it becomes your primary farm mechanism. Maybe I'm garbage at farm, but .65 attack speed and insanely low damage make it pretty hard for me to last hit. This can pick up all 6 minions with ease, letting you push your lane very easily.
Poor Distortion. Once your primary damage dealer (due to procing sigil of malice), it has now become a highly powerful utility. It's gap close lets you move in to land Ethereal Chains or move around enemies to land Ethereal Chains. It lets you jump over walls and can setup your waveclear (for sigil of malice). That's not to say it doesn't deal a considerable amount of damage, but it just can't compete with Ethereal Chains for poke power. Use it to end a fight, but you want to keep it for later in case something goes wrong.
And it's the ability you've had to listen to me rave about: Ethereal Chains. Why do I love it so. Allow me to show you the math. If you were to get it at level 1, ethereal chains would do 40+50%AP twice, for a total of 80+100%AP damage. But wait, there's more. With a 1.5 second delay before it deals the extra damage and chains them, it procs your passive by itself. It needs no other spells. That means that it does 120+180%AP. But wait, there's more! You may notice that between two instances of Ethereal Chains combined with a third hit from Sigil of Malice you have scored three hits. That's enough to proc your keystone mastery, Thunderlord's Decree , for a total of 130+190%AP. Throw in Fresh Blood and you're at 140+190%AP, not including other damage buffs from the masteries. That's enough to chunk almost anyone's health, and it's a far cry from the 85+40%AP damage from Distortion. So why choose Distortion first? It's really up to you if you want to poke or farm, as distortion sets you up for great minion kills. Let me just show you one last thing. At level 18, your Ethereal Chains will, without any other abilities (besides aforementioned masteries), lands 988+190%AP damage. That's a lot. But surviving to level 18 is the challenge, no?
Mimic is without a doubt, the most confusing ult I have ever come across. Allow me to explain it. Mimic has two different functions, and I will treat it as two different ultimates. Let's first look at the one you're used to, pre-nerf. First, you hit R. Then you hit Q,W, or E to activate an empowered version of the spell. This makes you invisible for a very short time, and summons a copy of yourself for 2.5 seconds. It sets your entire ult on cooldown, but does not interact with the cooldowns of your Q,W or E. To be clear, it takes two buttons to activate. 2. Dos. Deux. Two. II.
Now that that's cleared up, let's talk about what happens when you press R R. First of all, in order to do this, your ult needs to be off cooldown. The first press of R brings you to the standard empowered-spell selection. Now choose a place on the map, hover your mouse above the desired location, and press R. It now summons a copy of you who walks towards the nearest enemy. Once within range, it casts the last ability that you cast. Almost immediately afterwards, the duplicate disappears. So, it lasts a long time approaching the location, but upon arriving quickly disappears.
Runes and Items
Don't doubt me boy. I ran the math. It's nice to have 45% CDR with her, as it lets you spam her ult. Magic penetration is nice, as is initial ability power. If you have a disagreement about how much you need of something that's fine. Trust me that this is the most efficient way to do this.
I just don't know about items. I'm playing around and will post when I'm done.
This is under work, and will be updated more as I figure out how to mechanically, rather than hypothetically, play her.