I would rather it instantly, in the blink of an eye, takes you to the "do you want to search for another opponent?" screen on the multiplayer menu's because watching it is a waste of my time and the opponent doesn't have to watch it. You're watching that animation like a sucker and they're already finding new people to play with.
Give them a 60 second ban. If they do it again within 24 hours then make keep doubling it for every quit. I'd rather have that. Quitting should be = to closing game app, turning off console, power cutting out etc. So people WILL be penalised, no matter what.