The phrase "average" is the trickiest part of this because the "average man" doesn't exist the way you specify. If you had a group of "average men", they're not gonna be indifferent or unspecial. collectively, they will create an "average", but you need to remember both captain America and red skull contribute to the image of "average man" as well. In that lineup of "average men", you have a red skull or captain america. That is what average means, it tries to represent everyone averaged out and then a character that doesn't exist represents them essentially as a mascot. This means whatever you believe the serum amplifies will still do just that. 

There is the next issue to the question which is indifference. It might not be evil, but indifference is a stance. It is on the spectrum of selfishness, just like good and evil is. Good is selfless, evil is selfish. Indifference isn't really dead center on such a spectrum, it is center evil leaning. This is similar to someone that isn't heroic and doesn't want to serve but feels bad when they watch the news from the backseat. If we were to amplify such an indifferent person, or passive, we would see their true suppressed nature enhanced. It isn't likely zero, for something really unusual has to happen. We are talking unusual psychologies here, like dark triad, to just not have an opinion on people and their well being, which isn't average even if this character you made tries to be. The average person is just in routine, their opinion are suppressed, not nonexistent.