DBlade sustain wasn't enough, it's one of the reasons ADCs took Warlords in the first place. 3% lifesteal just isn't worth 450 extra health.
And then there's the new Botrk which might be a good rush item on champions that never bought it, making LS into Vamp first back a much better opener, but that remains to be seen.
Well, how much health is it worth? You're getting 300 health with the two extra pots from LS3 instead of dblade + 1 pot, no? Though dblade does give you extra base health as well, which should be counted.
New bork can be a good reason for sure. Ezreal doesn't have any reason to not go LS3 I guess. Probably not Vayne either, who should have a tougher time now with warlord's gone.
Caitlyn, though? She probably doesn't want to rush bork, or even get it at all. I'm guessing she sticks with her dblade.