I think Liss should just get fully reverted, especially her passive. A rework is supposed to add something to a kit, but Liss's one just took power from her main kit and put it on a passive skill, that we can't even control. Then her main kit got nerfed several times, until Lissandra's whole kit became "press R and spawn passives". I think that it's not healthy for the champion and the game overall when a champion's main job gets reduced to existing and spawning passives.
The w change, that made it go center-to-center instead of edge-to-edge, is something I don't understand either. Old w allowed you to kite and to display skill while dodging spells. The new w just forces you to stay back until you know you can outstat the enemy you wanna engage on, especially on champions with large hitboxes.
I gotta admit, I think, that making the E visible through walls was a good change that adds counterplay against her and that no champion should be able to blink over a large wall without an indicator or any kind of warning.
Liss used to be one of the most flexible champions. You could play TP or ignite, could take Electrocute, Aery, Comet, Aftershock, even Klepto. You could be flexible in itemization. You could lane bully, splitpush or teamfight. But Liss was never too strong in either role and did not go above 50% winrate until Aftershock came up as a counter to the Irelia, Yasuo and LeBlanc meta. Now with the removed scalings and mana passive you are forced to take aftershock to survive lane. You can barely punish bad players in lane because you are missing both damage and mana. You build Luden's to have enough mana, then get magic pen to abuse your passive dmg and hope you win the game because you won't be useful after that because of the removed scalings. You can't properly splitpush anymore because you run out of mana way too fast and your passive requires you to be in teamfight early. Liss's playstyle is very one-dimensional since the rework which shows how unhealthy the passive is.
Aftershock with Corrupting Pot and Dark Seal is a problem I won't talk about because others have done it in this thread and because I personally think, it's not what lead to Lissandra's fall.
To sum it up: I think the whole rework was a mistake and is a disaster in terms of balance and in terms of good champ design (except for the E visibility change). Liss should be reverted to her old state, especially since Aftershock and Dark Seal got nerfed and the assassin meta has passed, so she wouldn't be too strong in her old state.