Assassin Misconception?

So with this new update, Riot went through and changed a bunch of champions previously noted to be Assassins. In their process, Riot took these highly volatile champions and stretched out their time to kill. It seems that everyone is now upset because these champions: A. do not necessarily 100-0 champions in under 1 second, or B. still do so despite Riot saying this was not the goal, or C. do not have burst comparable to Annie or Syndra and thus mages are better assassins than Assassins are.

Now, am I correct here in assuming that everyone is basing the success of the assassin update on their ability to kill a target? Because the way I see it, Riot made every assassin with mobility and tactical decision making at the forefront of their champion designs and blatantly said that Assassins are not meant to be superior burst mages, but rather mobile and elusive finishers or solo combatants.

I feel like damage is important, but above all I feel that the way these champions are used should be their highlights. I feel as though there should be more debilitation going on, like "dealing 90% of the target's health nearsights them for 6 seconds" or "landing a full combo stuns the target for 3 seconds", not "okay, its hard to do but if you can land a full combo, they die." The latter line of thinking seems to be the root of everyone's frustration. Thoughts?