One other (subtle) use for Drakthur

it's surprisingly good at killing those slippery people. Since it reduces the amount of raw damage you need to deal to kill them, it's perfect for people who aren't very mobile like Talon and Pantheon who need that extra second of stickiness to kill someone but can't because they jumped or dashed away. This shouldn't really help Zed or Lee much because they are highly mobile already, but the delay is just enough to finish people off if they manage to escape your immediate zone.

With Nid, Lucian, Zed, Ezreal, and caitlyn being pretty common where I am right now, I expect to be using it a lot unless I am absolutely stomping and can kill them before they dash away.