What would you prefer? Instrumental Rationality is a bit of a mouthful, Common Sense is an abused term is means whatever the speaker believes in, and our super dictionary "Acting as to maximize expected utility" seems formal. I agree we pepper the word Rationality enough that it may turn off outsiders, but I am personally not seeing other terms or phrases that don't either under formalize to the point of meaningless folksiness or over formalize to the point of turning even more people off.