Fix tanks, ADC's, and assassins in one fell swoop

1. Delay but increase crit-build power-spike by separating IE crit damage amplification and crit chance onto different items while increasing IE crit damage amplification.

2. Substantially increase armor and magic resist on tank items.

3. Increase lethality and flat magic pen values. But temporarily reduce lethality and flat magic pen values of targets that were recently cc'd (including slows), this way tanks can protect their carries from damage by doing what they are supposed to do -- cc the enemy.

These three changes, in combination, will restore balance to the classes.

Explanation:

I) In principal, there is nothing wrong with marksmen building lethality. However, when this was a thing, Markmen weren't punished for sacrificing a crit-based build. They still handled tanks well enough and utterly destroyed squishier targets. Substantially increasing tank armor values will do a better job negating damage from increased lethality, as will reducing lethality of champions who were recently cc'd. If marksmen go a lethality build, they must be either exploiting a lack of tanks on the enemy team, planning to win early, or relying on another champion to apply dps to the tanks (e.g. cassio).

On the other hand, crit-based builds should be very strong late game and should excel at melting tanks; but the powerspike from a crit-based build should be delayed further into the game. Change IE so that it amplifies crit damage more (say, 300% damage instead of 250% damage) but does not increase crit chance. This would reduce the average crit multiplier of IE + zeal item from a 1.75 multiplier to a 1.6 multiplier. Now put 20% or 30% crit chance on another AD item. I would recommend a lifesteal item -- perhaps something like sanguine blade, where lifesteal and damage increases with autoattacks to emphasize that ADC's should be dealing consistent dps. The lifesteal could then be tuned to balance lifesteal for a crit-build marksman. This would help to further distinguish lifesteal items (exe., Bork never knowing its identity). Mercurial Scimitar would be the more defensive options, Bloodthirster would be somewhere in between, new sanguine blade would be the offensive option for a crit-based build, and BORK would be specialized toward on-hit champions and certain bruisers. I would also recommend some variant of wicked hatchet be brought into summoners rift. For example, a revised wicked hatchet item might deal bonus 150% of total AD times percent of current health as bleed upon a critical strike. The "times percent of current health" would allow this item to shine against tankier enemies without being overpowered against squishier targets.

II) increasing lethality and magic pen increases damage done by assassins and lethality-build marksmen toward squishy targets, but the increased armor and mr of tank items will more than offset these changes for tanks. In addition, tanks and carries with CC can mitigate the damage from lethality/magic pen builds buy using their cc. This reduces lethality/magic pen from being too much of a stat check, allowing skillful expression of champions to exploit or prevent the threat posed by lethality/flat magic pen.

A final recommendation -- I would recommend allowing alternative build paths on assassins that allow them to fight against tanks while trading off their primary job of assassinating carries. In particular, I would recommend giving AD assassins % of current health damage on abilities which would scale off of only crit chance -- a stat that few ad assassins would normally ever use. Combined with the new wicked hatchet recommendation, this would allow assassins to avoid feeling useless if they first pick into a very tanky team or if enemy tanks start snowballing; however, by going down such a build path, the assassins would forfeit their effectiveness at assassinating.