#4 Decline as a set-piece specialist
For a man who scored more than 50 free kick goals (for both club and country) in his illustrious career, his return has been poor in the 2015/16 and 2016/17 La Liga seasons where he just scored only once in each season.
Gone are the days when opposition teams don't want to foul a player anywhere near the goal when Cristiano Ronaldo is on the pitch. His set-piece expertise is part of what made him a great player at Manchester United and that's what prompted Real Madrid to pay a world record fee for him.
His knee injury (tendinitis) late in the 2013/14 season had a major impact on his free-kick technique. He modified it a bit to put less pressure on his knee which affected his ability to shoot from distance. Just to relieve him of the pressure, Garth Bale and Isco are beginning to see more of the set-piece duty these days.
Set-piece Goals (La Liga & UCL):
2015/16 - 9
2016/17 - 4
2017/18 - 0