Well...hypothetically speaking what if they could not fix the problem. And you would have them report it to this thread admitting they are stumped. What then ? That would pretty much make the server incomplete and cause a lot of people to leave because it will never be the "true vanilla" and it makes them look bad overall.
It's much better for numbers (their pride and joy) to leave people hanging. If it got out that major class breaking bugs cannot be fixed, who is to say it won't be mages next? Or warriors? They will lose face and people will lose confidence in their ability to maintain this server