Some things I would like to see addressed with Sejuani as a Sejuani enthusiast

Assuming that she's being looked at with the tank update.

Things I think need to happen:

Improve her attack animations. I don't mind that they're slow but they have absolutely no impact at all; the way she swings her weapon looks like she can barely wield it. Quality of life change, but still important.

Make her passive stronger, but more conditional. Free armor and slow resistance just for tagging someone isn't something that'll be easy to balance; if it's strong enough to feel noticeable then it's probably too good. If it was tied to something that required more commitment on Sejuani's part, then I think it would have more room to be made to feel good without being too powerful.

Return late game power to her. Sejuani should stand out as a late game investment compared to other tanks; where they excel in mid-game with big shields and high base damage, Sejuani should outscale them by converting her defensive stats into damage, and turning into a teamfight beast once she's close to full build.

Things I would like to happen:

Merge her E with her W and give her a new ability. I don't think that her current kit offers enough play between her and her opponents, which is why she became so oppressive in season 5 when the game shifted in her favor. This lowers her ability to permaslow from range, but we can compensate her generously for managing to stick to melee range.

Make Q more telegraphed, but more rewarding to land. Same reason as above; it's a short range dash but it's incredibly hard to dodge short of burning a mobility spell. If there was more gameplay for both people then I think some more power could be given to it to make it more satisfying and feel less bullshit to get jumped on and permaslowed. It's not really a problem spell, but it'd still be nice to give it a little more oomph.

I think Sejuani has a strong foundation for a kit, but could be given a handful of changes to make her feel better to play as and against. I hope she's considered for the tank update.