Well First of all, it will avoid the constant spam flow.
Secondly. I believe that IP banning has already been implemented, and proxy connections are automatically disconnected so I don't see how a flame troll can get away from it more than twice.
Multiple accounts won't do good in such a situation either.
First of all, it will not avoid the constant spam flow, it will only delay it.
Second of all, people can still IP evade. We constantly ban people for ban and mute evading, and the restrictions we have implemented only delay the spammers.