Armor pen changes are mostly good, but some issues

The change to dominiks is great if your aim is for it to be used by squishy ADCs and assassins. I also appreciate the option to itemize a last whisper alone to deal with early armor stacking.

Black cleaver change is fine with me. I think it's a good idea to reduce the synergy of it with last whisper without impacting the effectiveness of last whisper alone. It's also expected since most other bruiser items were nerfed away from AD towards defense.

Reducing damage in masteries across the board is probably a good idea. Although I like being able to significantly shift the power of my champion based on tailoring my runes and masteries, if most people are taking a lot of the same maximum damage masteries then it kind of defeats the purpose of the system. But I am concerned that champions like Talon will suffer unduly from not being able to wring every last ounce of damage they can out of every phase of the game, where the difference between winning or losing can often be measured in slivers of left over health. Hopefully Riot will keep a close eye on individual assassins to see how they are doing after this change.

I disagree with reducing the amount of lethality on ghostblade. I don't see it as necessary. Especially when they stated that lethality was suppose to scale better into late game in order to offset it's worse scaling early game. Armorpen always fell of late game, and that was one thing they wanted to fix for us. Granted, it scales faster now, but that's 5 less armorpen and about 2 less from masteries, which means you can no longer cut through the base armor of most squishies at level 18 even with maxed lethality items, runes, and masteries. Which is exacerbated by the fact that it's easy for mages and supports to itemize some armor and health into their builds - meaning sometimes only the ADC is a target you can expect to assassinate, which narrows your role so far down that your value on the team is questionable.

I am glad you are waiting to tweak edge of night, but I have to point out that most people want the wrong things changed about it for the wrong reasons.

1. The efficiency of Edge is not a valid complaint. Maw was just as efficient before it. It was an AD/arpen/magic resist/magic shield item. Edge is just a replacement for maw in the assassin build order. Maw was just as powerful for an assassin against mages as edge of night is. They just work differently. But nobody would want to build a Maw now on an assassin now because lethality is mandatory to do your job.

2. Having damage and magic resist on the same item is not a valid complaint. AD assassins have to deal with 70-100 base armor at level 18. AP assassins and mages only have to deal with 30 for most, and 50 for fighters/tanks. AD needs all lethality runes, masteries, and items, and they still can't negate the base armor of most squishy champions. Mages can negate the magic resist of all squishies with two items, or one item with runes and masteries. Mages have an abundance of HP/AP items for added defense that come equipped with additional tools like slows, heals, and a dash. They have a nice armor/AP item with a statis, and an MP/AP item. In short, mages can itemize defense against AD assassins without compromising offense much. They can also itemize defense without sacrificing MPEN. AD assassins, on the other hand, have no viable HP/AD options (especially with cleaver nerf), and even if they did they are locked in to using three of their slots dedicated to lethaity/AD just to be able to function, so it leaves little room for hybrid defense/offense items. You'll probably want a last whisper too, to deal with those who build armor, and boots. So maybe you've got one slot left to play around with. That is why edge of night, and the old maw before it, made sense as an assassin item that granted you magic defense without sacrificing offense. Because the mages can itemize to counter your offense while still getting AP and MP to kill you, but without magic defense in your offensive items you have no real way of dealing with that. Schimitar is not a viable option because you'd have to delay your lethality and armorpen too long, which are non-negotiables for an AD assassin. An early hex is arguable, but you're still delaying damage to get it. You'd need to be getting seriously dumpstered by a magic user to the point where you decide that you can't kill them with extra lethality anyway, so you may as well just try to not die while you farm up.

3. Having said that. I do think there is room to rework the spellshield in some way. Whether it be duration, cooldown, or even the way it functions. However, when you do that, you have to keep in mind that EoN is basically a strait replacement for the old arpen Maw. So unless you want edge of night to be a strait up nerf to assassin gameplay, the spellshield has to be effective enough that someone would consider it a boon to the assassin gameplay to have edge versus the old maw. Remember, edge was suppose to help out assassins, not nerf them. If you make edge's spellshield dumpster tier then you may as well just give us back the old maw, increase its damage by 10, and reduce it's resistences by 10. But I'd rather have a functioning edge of night because one of the chief concerns of an assassin diver is not merely magic damage but any initial CC that might be thrown at them to interrupt their burst.

4. It's not a problem for lethality stacking ADCs to build it either. You have to remember that any ADC who builds lethality is basically turning themselves into an AD caster mage. They might pop squishies like cheap balloons (which max offense burst mages can do too), but they are completely useless against well armored fighters, bruisers, tanks, or even mages with lots of HP/AP items and an armor item. So any ADC that builds lethality is often doing their team a disservice, because their team probably lacks sustained auto attack damage from other sources to deal with the enemy tanks.