Nice to see you over here from Twitter Your Poppy has really come along.
Overall she’s looking really great! You’ve done an awesome job of adapting Poppy to fit the Mecha Kingdoms thematic. You’ve found a great balance between the asian shapes and the sci-fi shapes.
You’ve also done a great job of adding visual depth by getting a range of different colours and values in there. I particularly like the update you did to the Ult cast windup.
For the W area, I would suggest a few things to help this effect. You should try to define what is your primary Area of Focus element, and what is your secondary element. (you can read more here about areas of focus: Anatomy of a League of Legends missile - Part 1 - Creating Areas of Focus )
You should reduce the opacity of the central circle, so that it is a secondary element. The primary element should be the ring on the ground, as this is the area important for gameplay.
I also think that you should reduce the frequency of the hexagons on the wall. The decal on the ground has a great balance of detail and clarity. At the moment, the high amount of detail on the wall is drawing attention from the decal on the ground.
For the E, I really like the value hierarchy you have, with the bright values at the front, and the dark values behind, it helps to show the direction she is dashing!
However, I think the trail texture reminds me too much of Hextech (though this may just be personal preference, as I have made hextech skins before XD )
I think if you could design a new trail with shapes more inspired by the existing VFX in the skinline, it could match the thematic better.
For the ultimate, I think you could increase the strength of this spell, by adding some soft glows to the pillars, making them feel like they’re glowing with energy. Additionally, at the moment, they have a very even value across the entire column. If you made the top brighter and the bottom darker it would help to define what your area of focus is. It would also allow you to add saturation: most of your other effects feel red, whilst this one feels a little bit pink.
Overall you’ve done an awesome job, great work!