Angela Merkel is certainly more powerful and so are a host of other politicians including the PM of Australia.
Look at it this way: The United States is the most powerful country in the world, the only remaining true superpower. For the last three years, there has only been one person who consistently faced up to and fought the creeping fascism that is the Obama administration. Ergo, she is the most influential woman in the world. It’s not the position she holds, it’s what she is doing.