Hi,
a: There are two versions if I am not wrong. One with a faster tempo than the other.
b: Would that you weren't...
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Hi, in this case, is b trying to imply a isn't right? Yes. Roughly speaking, it means 'I wish that you were not wrong, but I think you are wrong'.
A is trying to imply a condition so is it wrong to imply a negative state? No, what b says is OK.
The construction 'Would that you . . . ' is rather literary.
Best wishes, Clive