Going in the right direction but this idea won't work because of abuse potential. Imagine if enemy team is composed of 4-men premade and a solo queue. You know the rest.
Another abuse example would be situation where your team's behind, so you get one guy to close game client and reconnect right after, which isn't going to cost too much but it forces enemy team to vote once on someone to afk. Needless to say that's going to cause some conflict between them and might tilt their team.
I personally do like your approach though, the end idea of making the team numbers even is appreciated, just that as things stand it probably isn't going to work as ideal as it can be.