Yeah that seems fine, but the problem with the script is something I saw in Jim's Vid. They Name the bots offensive things and the chat script wont censor the names of chatters. So that would have to be manually dealt with.
And again, it's also just another system that Twitch would have to impliment and the botters would get around it eventually. The thing is that any solution for the most part is temporary. Because eventually someone will get around it.
The best solutions honestly seem to already be in place. Follower only chat with a several hours time flag, sub only chat, and emote only chats. These things are the best answers to the problem right now and for the most part do seem to fix and control things.
Is it annoying? Yes. But it works, and you just gotta roll around it.
Keep in mind that as @McElroy
mentioned above. It's not only these LBGT streamers that get botted. The LoL tournament was botted yesterday, and I'm sure the mods just set the chat into a different mode to deal with it for a while.