I would argue that your last version is actually the most readable. Obviously, opinions are going to differ as they always do, but my preference among your exam

I would argue that your last version is actually the most readable. Obviously, opinions are going to differ as they always do, but my preference among your examples is 3 over 1 over 2 (I cannot imagine preferring 2, because the difference in whitespace amount is easy to miss at a glance). There's bound to be some resistance and an "awkward feeling" at first, but this does seem like a nice suggestion. Unfortunately, it's not a change that you can just apply to an existing programming language, but perhaps it would be reasonable to start by warning and eventually erroring where whitespace does not fit the existing precedence rules.