older comic heroes that pre date Superman 

The Tarzan illustrations go back to the books, before the cartoons and TV shows, the loincloth, often leopard fur or deep brown hide, and the deep tan skin he has 

When Superman was created he was drawn as Tarzan, the trunks and the muscles - in B&W there would be no need for Tarzan skin brown and Superman's blue tights and shirt - they were added after, then the famous S and of course the cape - the red and blue colour scheme we all know 

Batman was done in a similar way, and of course with big reference to Zorro in how his cape and cowl work, all black

 For the comics, Batman was done with grey and blue, and had the trunks 

As we saw with Henry Cavill, the one piece blue with no red trunks does work, and no modern cinema Batman has trunks they way the comics and the Adam West version had, as well as being all black - Keaton, Bane, Clooney, Affleck, Pattinson .