Regarding the Warlord's Bloodlust changes on PBE
I like what Riot tries to do with Warlord's Bloodlust in general. An autoattack that grants you a decent heal and more movementspeed for a while can work well with some ADCs.
But on patch 7.5 the keystone isn't as good as it should be (if you ask me) because it feels almost useless against tanks, while it works quite well against squishies and is most effective against minions (due to no resistances) which is a kind of paradox since you want to take this mastery to kite against tanks.
Therefore Riot put some changes on PBE which are nice in theory but hurt a certain someone. Well they don't hurt her but the change of Warlord's Bloodlust won't help her as much as it possibly helps other ADCs. I speak of Vayne.
On patch 7.5 you get 1-50% lifesteal which works well with Vayne's Q ability. On PBE however the heal is based on total AD (which won't include the extra damage of Vayne's Q).
The approach of this change (to make the heal unattached to the enemie's resistances) is the right one but I suggest a different change which will help champions with autoattack amplifying abilities.
My suggestion would be the following:
Energized attacks heal for 5-40% {probably different numbers} of damage dealt (Calculated before any resistances or reductions are taken into account).
Like it is on Thornmail. This would help Vayne to get something out of her Q and since Fervor of Battle doesn't really suit her, she'll finally have a keystone mastery she can be comfortable with.
Let me hear what you think about my suggestions. :)
P.S. Sorry that this post is so Vayne centric. However this can be applied to many other ADCs (Caitlyn, Draven, Ezreal, Jhin and Jinx).
and/or 
) and end up healing very quickly because of their high attack speed anyways. But champions like Jhin especially, who scales really well with raw AD but has the absolute lowest attack speed average for the entire game, would benefit greatly from this change since he will not get enough return out of the life steal items to validate getting them over raw damage (mainly crit damage which on him turns into raw AD and lethality/armor pen).
, now i am kinda limited to just Grasp and Fervor
rely a whole lot more on-hit damage than AD. Against squishies, I was healing about 200 HP per energized attack in the late game. The change is gonna cut that down to 60 HP at level 18 with the usual Xin Builds.