Well Reasoned Top 5 Balancing Needs (Overpower)

There are a lot of one-off threads with folks yelling, screaming, flaming, or fresh off a loss and just venting about one champ or another. So let's settle down, do our research, and try to really figure out who needs what. Please list your top 5 choices for bringing down the power level of a champ, with evidence and reasoning.

Include:

• Why the champ needs to be balanced(high win rate? high ban rate? pick rate? toxic mechanics?)
• Evidence of the above(aka data supporting the claim, or a well reasoned explanation if the champ is not considered "good" but still very anti-fun)
• What specific portion needs balancing
• What you might do to balance it

I would really like to see well reasoned opinions on what the community thinks of the state of game balance, and create a discussion to help further the goal of creating a fun game.

Please: No flaming. If you disagree, respect the person you are disagreeing with. Respond to specific points with quotes, and stay on topic. Let's make this a fun and productive thread!

Edit: Please keep posts on topic.