Speaking to Weekly Famitsu, Hideo Kojima revealed that he was that close to removing the series' iconic exclamation mark from the upcoming Metal Gear Solid 5.
"I actually considered not including the '!' mark that appears when enemies discover you," he said. "… Considering the console specs, it would have been possible to substitute with facial expressions and gestures."
Fortunately, the rest of the team didn't get carried away with Kojima's whim. "The staff said, 'if you get rid of it, it'll cause an uproar!'" And thus, the "!" remained.
Kojima also decided to keep another one of the series not-that-realistic iconic features: the cardboard box camouflage.