The current state of Senna.

The recently popular Glacial Augment + Frozen Mallet build for Senna is pretty damn overpowered. She already has a free Phage passive built into her kit, and the slow from both Glacial Augment and Frozen Mallet on hit make her pretty hard to kite. Top that off with her insane range later into the game, and you've got an adc that just won't quit.

Thats not healthy.

Some suggestions? Nerf the movement speed bonus of her passive later on. Early in the game its pretty okay, but i feel like it just ramps up too much as the game continues.
Also, put a cap on the range she can receive from her passive like you did with Kindred. Its not healthy to have an adc that out-ranges literally everything.

Everything else, except for the width of her q, is pretty fine after she's gotten some tune-ups in the recent months. I just hope it doesnt turn into another kassawin type situation.