Personally changing a hair color or style is not very transformative. Putting on weight or losing weight or piercings, etc are verified transformations. Where was Sigourney Weaver in Aliens (3?). She dropped weight, toned up and shaved her head. Or what about Linda Hamiliton of the Terminator series? Cameron Diaz in Being John Malkovich? Glenn Close in Albert Nobbs? Hillary Shawnk for Boys Don't Cry and Million Dollar Baby? Half of the examples were weak or invalid in my mind.