It should absolutely NOT be removed. People who leave games on purpose almost always doom their team to lose, you deserve a penalty for that. Doesn't matter if you're getting steamrolled, ganked and killed at spawn, take the beating, accept your rewards and move on. If anything getting destroyed just means the game will end quicker.
Even if you're afk that deserves a penalty. You could argue that the time in which it takes be be removed should be longer, but if you leave your team long enough to get kicked while they fight a 3v4 you can put up with a 15 minute penalty. I know stuff happens in real life and you can't always be at the screen, but it's 15 minutes. Do whatever needs to be done so you won't be interrupted next game, if possible. Its not as though you've been banned for the whole day
Know what happened before the ban penalty? In dominion people would start quitting as soon as one team took 2 zones, or God forbid 3. Not even 60 second into the match, if a team took A and B at the beginning the other team started quitting. All it takes is one person to abandon ship before their team would follow because they didn't want a bot hindering their team. People who joined to replace those bots would leave immediately after seeing that they've joined a losing match
There are some interesting suggestions though, different ban timers for different game modes, steel/xp penalties for leaving instead of matchmaking bans, and PvAI quitters being exempt from bans entirely. Those topics are far more worthy of discussion than simply removing the penalty entirely
What I would love to see would be a prompt in the Main Menu allowing you to rejoin the disconected match. This could be applied to both random disconnects caused by lag, allieviating the dissapointment of having been disconnected in the last three minutes of a Breach round and AFK kicks aswell, giving incentive and possibility to make up for the disconnect. Having essentially wasted time in these cases is not fun.