olbertfrog said:

Wasnt aware that Cameron had an habit to tinker with his movies.

Is there any article or comparaisons somewhere about this?

Here you go. Basically they're new vs old releases comparisons that clearly shows the difference in colors.

It's also worth mentioning that Aliens and Titanic got some things removed or added by CGI in the latest releases. Haven't found anything for Terminator so far.

The worst thing is that the latest releases have far superior resolution than all before but having the wrong colors, fans can't choose between original and altered. Sure, there's the old blu-ray of Terminator but the picture is blurry and full of dirt, and there are HDTV broadcast captures of Aliens and Titanic but they're compressed.

I don't know what it is about the blu-ray era that made previously respected directors go back and change their most popular works. There are way too many examples. Maybe they don't think people will buy the same movies again unless they look different? Different being new in the eyes of mainstream consumers?