Sure, I would consider any of those factors, if Terminator Genesys was the only example of Hollywood inserting Chinese characters and settings.

• If you remember, in The Dark Knight there is a Chinese character that gives Batman a reason to visit China.
• James Bond also visits China in the latest film, Skyfall.
• In the script for Looper, the main character retires and marries in Paris, France. The producers shifted Looper's international scenes from Paris to Shanghai.
• In X-Men: Days of Future Past, Fan Bingbing, the superstar Chinese actress/model, was added to play the mutant Blink.
• For Transformers: Age of Extinction, Paramount Pictures shot parts of the film in Hong Kong, cast Chinese star Li Bingbing in a lead role, and worked with local companies to promote the film. It made more money in China than it did back in the United States.
• James Cameron said he was considering inserting Chinese elements into two sequels to Avatar, saying it would be "logical" to have Chinese characters on the planet Pandora.
• World War Z deleted dialogue sourcing a zombie virus outbreak to China in order to not upset the Chinese Government and audiences.
• In the remake of Red Dawn, the enemy was digitally changed in post-production from China to North Korea.
• In the script for the movie “Pixels,” intergalactic aliens blast a hole in one of China’s national treasures – the Great Wall. The scene was deleted by producers so they wouldn't anger China.
• In the Marvel comics, The Mandarin” is Chinese-born and one of the greatest comic book villains of all time. China does not like being portrayed as villains. So, for Iron Man 3, The Mandarin was transformed into a Western actor simply hired to play a role by the real villains. Not only that, for the Chinese release they inserted a scene of doctors, played by major Chinese movie stars, discussing surgery on the superhero, even though the scene made no sense and seemed like it was from a different film

So you see, China's audience has risen in the recent few years to rival that of the US and Hollywood has learned to cater to that audience.

I would consider your other arguments except for the fact that in the film Terminator Genesys, there's no reason for the part to be played by a Korean actor. His character is not explained, given no backstory, or explanation. He shows up, does an action scene, and is never spoken about again. It was very obvious they just threw in a Asian-looking Terminator to cater to the Chinese audiences.