I'm for keeping it as it is.
- Newer users may feel unable to socialize (although the TeamSpeak isn't intended to be an ongoing party)
True, if they wish to speak with other people, they could poke the owner of a populair channel to speak with them though.
- Less admin availability aside from PM/poke
PM/Poke is enough, just poke the admin, and he can come into a public channel, and both can talk.
- People can't follow you (harassment has been a previous issue on our teamspeak).
Yeah it really has been, this would completely fix it, for example : Adwad's situation, where everyone followed him around, bullying him, and he then kept on saying : I'm going to suicide. (never happened, he was lying)
Things like this could happen again without private rooms, but maybe even worse.
All the other advantages are great aswell.