I think the subjects should be chosen from among all living American citizens, by lot.
"And this year, the five dollar bill will bear the portrait of ... Mrs. Carla Winstance of Ridgewood, New Jersey! A big hand for Mrs. Winstance, people!"
Alternatively they could just leave a blank space in the middle of each bill for people to draw their own pictures.
In america, instead of uplifting images and grand ideas, you'd probably more often see hateful drawings of black lynchings, commercial starbuck coupons, and crudely drawn genital cartoons.
Well, my aim was to have the design of the money truly represent America ... so ...