[JohnFen]

Thank you for this moment of enlightenment. As an American, I totally hear "I would recommend/suggest/consider changing this code to this" as a particular flavor of "fix your shit". That flavor being that the person saying it isn't mad about it, but you really do need to fix your shit. If they're mad, they'll say "fix your shit".

My enlightenment was that this meaning is so instinctive to me that I doubt that it would occur to me that it could be misinterpreted.

[watwut]

That is the thing. I would take this suggestion as optional. For me, it means that you have some preference, but are not strong about it nor care much. I would not interpret it as "fix your shit".

Polite and direct to me would be something like "I think you should change this code".