I've found online that apparently your signs deal a lot more damage if you don't have any sword equipped or you have your sword sheathed. But does it also affect the power of your Quen shield for example? And what about other signs? Does having no swords for example simulate a double sign intensity maybe? Does anybody know this?
It affects every sign. Tested on Alt Yerden. It does appear to be about double intensity.
Since you mentioned Quen specifically, yes, it does get the increase, but quen doesnt scale well with intensity, so you might not notice.