I think it would be really open to abuse. You're losing the match? Just disconnect your internet and you don't lose anything.

I think the current system is worth it, because you shouldn't have internet problem too often that it would cause an issue in the long run. Losing 50SR every now and again isn't a huge problem, it can quickly be won again, it's just a matter of winning a couple of games to get back on track. If it does happen very often, maybe your internet connection isn't reliable enough to actually play competitive games. It's kind of an implied contract: you're playing a competitive game, you have the responsibility to make sure you don't have too much connection/ping problems. And if you do have them and you can't do anything about it, you're just penalizing your team by playing competitive games (Just a couple of weeks ago I ended 3 games in a row in a team with a guy, playing DPS, complaining about the fact that he had 300 ping. Dude, fix it or go in quick play).

And I say that even though I lost a match yesterday because Blizzard's servers were fucked up. My internet was running fine, but at one point I lost connection to Blizzard's servers, and I couldn't even log back in for a full minute.