So last patch before this patch they nerfed his Q cause riot wanted people to max his E first if they wanted to have lane pressure and Q for CC instead.
But this patch they pretty much remove the whole "maxing E first" thing but putting power back in his Q. (The E>Q Combo deals more damage)
But I feel like there hasn't been enough testing around the Q nerf to actually get him a 2nd nerf to his E too. Honestly, this might make him really weak compared to many other champions in my opinion.
Now you don't get barely anything from maxing E, so maxing Q and building some AD will give him the power he needs to keep up his laning phase.. But that just feels very wrong for a CC machine who got implanted poke.
The last Sion nerfs over the years has been all over the place too. First they nerf his W early-shield so much he was unable to jungle, then they nerf his Q but buffing his E so he became a tank with poke. Then the nerf his Q an additional time to make people max out his E first.. And now... They mega nerfs his only "decent" damage ability(E) directly after the previous mega nerf to his Q...
What are they trying to achieve here? Only people in esport play him right now cause of his high amount of map-pressure and CC. If you nerf his Damage and waveclear to the ground then he can't do what he is good at and will fall down to the state of Nautilus top.
Honestly... Sion hasn't even got enough testing for 2 big nerfs in row.