I think you're applying 'change' and 'restrict' to different things.
Cold water becomes hot water.
is not redundant or a redundant version of "Water becomes water." or "Water becomes hot."
There are things and then there are the words to describe things. If your use of 'water' is about water in general, then applying 'cold' to 'water' is not changing the meaning of 'water' it is talking about a different concept, namely the subset of (the 'restriction' to) water that is cold. If you apply an adjective, you're now talking about a different thing. It doesn't change the meaning of 'water', it's referring to something different, water that is cold.
Cold water becomes hot water
is talking about something slightly different from sentences where you remove any of those words.