Well, it wouldn't be fair to say that TWI is doing nothing though, they *do* work on bug fixes and they answer to requests from modders. You can see on the Level Design forum, that they are about to release a patch.
The problem here, is the conditions for white-listing. Instead of the implicit and restrictive rule:
The mutator must not affect the gameplay in a way that the user cannot understand that it is not acting like the stock game.
There could be this rule:
The mutator must provide clear indications of the modifications it makes to the server.
A way to apply this rule, could be to have a second "Server Welcome Screen". The content of that second welcome screen would be used to display the server-specific changes, mutators, etc, and each mutator could provide a text explaining the effect, in a short explanation. Then the user clicks 'I understand'. There could even be visual cues, indicating how deep the changes are, and TWI would provide a rating that the modder has to display on that page, RED for a mutator that changes a lot, Yellow for medium, and green light modifications.
Players should be aware of the mutators the server are using, and the settings of those, and the server settings too. I'm sure the players would appreciate that kind of details. Many have asked for it on these forums. Anyway, it's just a quick idea, I'm brainstorming here, but the point is, that I'm sure it is possible to find a solution to this issue, and I hope TWI will provide one, instead of simply black-listing.