For Vayne, the Condemn change increases the damage to 150% when they strike a wall and the damage is now instantaneous. It wasn't already enough that it adds a stack of her W that could proc the 3rd-hit effect and is a point-and-click free disengage I guess. The explanation (At least from what I understand based on what's written in the patch notes) given is that it is to aid her in last hitting minions.
Now I don't play Vayne, but what Vayne player uses their E to last hit a minion? She's already got her AA's and if needed, the AA-Resetting Q that deals increased damage, so why waste the E on a minion? I would think that would practically be inviting the enemy bot-lane (And the JG if they are there) to go on you because your disengage is down. The Vayne's I have seen (Both on my team and the enemy team) never have used it, expect perhaps those that may not know or understand how Vayne works.
Next, on to Lucian. (I don't play him either, so I'm just writing based on my experiences from that same limited third person viewpoint as with Vayne)
They buffed his R, claiming he needed boosts so he won't fall off as much in the late-game. Here's the problem; Lucian (Based on my understanding) is SUPPOSED TO FALL OFF LATE-GAME! That is supposed to be his intended weakness, that he is strong early to mid game, but loses effectiveness when the late-game comes. He is supposed to want to smash his lane in the early and mid and close out a game before his opponent can outscale him.
Now this buff may not entirely remove that weakness, but it brings up one of the problems of Riot's balancing over the last few seasons.
They remove (Or weaken the effectiveness of) what are supposed to be INTENDED WEAKNESSES of certain champions or champion classes.
I know I'm beating a dead horse with this example, but just look at Riven.
Riven's weakness is SUPPOSED to be that she has no real sustain, as she is a Skirmisher, and not a Fighter or Tank. Part of the description of her Sub-Class states this: "they are instead armed with situationally powerful defensive tools to survive in the fray", with her E shield supposed to fill that "situational defensive tool". If she doesn't use it wisely, or in the correct situations, it's not supposed to benefit her all that much.
But then Conqueror came along and it single handedly removed that weakness because of the fact that she heals off the True Damage she deals when it is stacked. I admit she was more of a problem with it before Conqueror got reworked/changed, but the existing version still circumvents it partially.
Then there is the change to Xerath from this very patch; they've equalized his R range across all levels of it rather than it scaling with each level. It's more changes to further speed up the game.