I remember reading an interview where Hideki Kamiya talked about how disappointed he was that the Wii port of Okami cut out the original credits. He used a Japanese word that I can't remember, but he explained that it referred to all of the emotions, all of the love and blood and sweat and tears that went into something. And he said the original credits theme embodied that concept. It contained all of the emotions he wanted people to feel during their journey.
Ideally, devs would approach their icons the same way. They spent years working on their game, working their hardest to create something they hope will make other people happy. There are feelings they want people to feel, memories they want people to have. The icon is probably the last thing they create, after everything else is said and done. It could be an opportunity to sum up the game's sense of adventure and convey the feelings they want us to feel. Same for a box if you buy physically.
Look at the Mario Kart icon and how you have Mario, Peach and Bowser joyously racing toward the screen on a rainbow-colored highway to heaven. Look at the new SteamWorld Dig 2 icon and how you have Dorothy exploring a deep dark cave lit only by bioluminescent shrooms. They're beautiful, and they feel like something premium, something made by people who care.
On the other hand, a giant face, or a letter and a number, don't convey much of anything. I'm really appreciative that the devs care about their fans and are listening.
