I think you are overemphasizing the role of the Zero Reply status -- you're making it sound like as soon as a thread drops off the Zero Reply list, then its chances of getting answered are seriously reduced. That's just not the case, and like it or not, sometimes the only way to move the discussion forward is to ask for more info. There's nothing wrong with that, and I'm not sure that trying to discourage people from replying is the right approach.
Overall, and to state the obvious, the main key to a successful thread is for the OP to use a meaningful title and to include the relevant details of the situation they're dealing with. If the OP doesn't do that however (which is especially common in newbies) then if someone follows up with a post asking (for example) which distro they're using because it hasn't been specified, then that followup post in fact almost becomes necessary -- without it, anyone else trying to help with the question would be forced to guess at the details that were omitted. Granted, not every answer will depend on the distro being used, but for some questions such as how to install new packages, the method will be different depending on the distro (eg, YaST, installpkg, apt-get, and so forth)
I agree that people should refrain from posting if they have nothing useful to add or if they just want to express an opinion, but making a good faith effort to assist by asking the OP to provide any necessary details is something that I think should be encouraged, not discouraged.