Instead of potentially nerfing Sejuani, consider just tweaking her power curve

These changes I feel would be a good solution:

**Make W have a 10 second cooldown at all ranks rather than 11/10/9/8/7. Lower scaling HP per level a bit. Increase base HP5 and/or attack speed. **

This is a champion that isn't statistically OP, just possibly a tad too good due to the nature of the current game and the state of items. Flat out nerfing her would probably make her suffer really hard when the meta shifts again. Imagine if counter jungling became big again?

So I'd say buff her early clear a bit, but make her scaling worse.

A flat nerf is not the right answer. Her power curve just needs to be looked at. At that point, she can feel better balanced while meta shifts wouldn't hurt her too badly.