My Top 3 Most Powerful Politicians In The World 2017:
1. Xi Jinping
2. Vladimir Putin
3. Donald Trump
Honorary mention: Angela Merkel, but since that migrant crisis, she is only losing position more and more.
I would agree with your selection, perhaps not in the same order. And regarding Angela Merkel, she was never in the top 5. How can we call her powerful, when is is forced to follow the orders from the Turkish president Recep Tayyip Erdoğan?