So since my last post on Senna:
Her win rate has continued to rise from 53.8% to now 54.5% as AD. As people continue to learn to play her, I suspect that will only increase further. She obviously needs to be nerfed. So I've been thinking about it and I think the best way to nerf her is to hit her ability to scale on her passive. My suggested nerfs are as follows:
AD Stacks per Mist lowered from 1 to .75
Requirement for Bonuses raised from 20 to 25
One of the common complaints I've noticed is even if you beat Senna in lane, she quickly outscales you both in damage and range that you can't go near her after the 20 minute mark. This slows down her growth and increases the window of opportunity to take advantage if you beat her down in lane. I think Riot should start with these nerfs and see how they affect her. However if she requires additional nerfs I would suggest one of these as well:
**Additional Potential Nerfs:
Senna Starting Attack Range lowered from 600 to 575
Senna W Scaling with AD changed to AP
Senna Ult Damage lowered from 250/375/500 to 200/300/400
Obviously you wouldn't do all three of these but these nerfs would also help bring her under control I think. I like the Attack Range nerf the best because it gives champions who she currently outranges a better window to fight her in lane. The W scaling with AP could open up potential new builds but it also hurts her AD burst which is nice. The Ult nerf would kind of hurt her Support role which I don't think is the problem so I think that's the least viable nerf out of these three although you could counter buff the shield it gives which might solidify her more into that support role.
So these are my thoughts so far. Feel free to throw your own ideas at me of what you think will work and what won't.