I get what you're saying. But, at this stage, I disagree. I've been at the end of a game (lost the game btw), and before the ending cinematic appears, POOF disconnected and kicked back to the main menu. Even though we were thoroughly run to ground, I never wanted to just quit out. But, that's just me. I stay no matter what! Again, with this being in beta, the disconnects are to be expected. I think they are using EA technology and planning for their servers. We can only hope it gets cleaned up.
Now, I do agree that if it can be proven that someone rage quits or leaves early without it being a connection issue, I think they should penalize that player. It's been done in other games before, but I'm not sure what, if any, effect it had.
Have the same problem in 1v1's, higher tier its filled with Orochi's and Peacekeepers who spam their guardbreak, storm rush or side step abilities. If you manage to be quick enough to block them they will leave. This isn't some oh he charged at me and disappeared, (which happened to me only once) no he ran out of stamina I punished him with a combo and nearly killed him and he stands still and exits. And replaced by a bot version of him that's better.