Considering how fast these games are, whether you stomp or get stomped as early as 10 minutes, allow us to surrender at 15.
If not, tell me why, Riot.
Edit 1: So I have been playing more games and it seems to me like those games that lasts longer than 25 minutes have either team trying to outstomp the other team in order to close the game. One team fight, red side comes out the winner. The next teamfight, blue side comes out the winner. Whoever can smartly benefit from winning the sometimes-onesided teamfights will most likely win.
Otherwise, the game is mostly one-sided when one side snowballs like Gragas on crack rolling down a snowy hill. It's not a struggle between two similar powers for the majority of the time. It's a struggle between the higher and lower powers.
Edit 2: Things have gotten a _little_ bit better since my last edit. However, I would still like the idea of surrendering at 15 when the Rift is filled with my team's graves and gold on my enemys' side. Mostly, this would be about those types of games where it is clearly obvious that your team is being stomped into the dirt. Other factors may also apply.