My initial impression would be that there's nothing wrong with most Google questions, because that type of question can always benefit from an excellent and authoritative answer - a literature review if you would. A question would be good for this site if either 1) the current top search results give the answer without explanation (in which case maybe ask "explain why", turning it into more of an "expert" question) or 2) the top Google results are conflicting (in which case the question should link to the conflicting sources so that an answerer knows that they must refute the incorrect answer).
Consider that there is a difference between an "expert question", which must be about something that only an expert would know, and an "expert answer", which could be an answer to an expert question, or could just be a clear, well-researched answer to a question that has plenty of Google answers, but no Google explanations.
The only bad Google questions are probably those for which there is no explanation possible. Either the answer is obvious or can be found in very common references (what frequencies does the 70cm band cover) or the answer can be easily found and cannot be explained (Is ham encryption legal in the US? No. Why? Because it isn't.) There was a blog post sort of about this, especially the guidelines near the end of the article. Many of the best questions are those which have a little subjectivity. These questions have an answer, but require some explanation as to how to arrive at that answer. (The followup to that post is pretty interesting too.)
One note on the question you linked - it's not really clear which side of the spectrum that falls on in terms of scope. The way it's worded, it's a really small question - please find me a resource that answers this question. However, the subject matter is so broad that it could probably be split into many smaller on-topic questions.
So, perhaps in summary, while questions should have at least some of these qualities:
- expert-level subject matter
- a single factual answer
- which can be justified with references and data
- which can be explained such that the questioner can arrive at the answer themselves
- which cannot be found by typing the question into a search engine
It isn't necessary that all questions have all these qualities all at once.
To follow up on the example question you provided, consider breaking that question down, and consider the question "How do I select components for receive RF, IF, and AF filters for a 20m SSB receiver?". You can certainly find an answer to this question on Google, but the question asks for much more. By taking your very broad question which could be answered by a single link to a single schematic and breaking it up, this question could be answered by an expert-level explanation of choosing RLC values, active vs passive filters, crystal vs RLC filters, and even carbon film vs wire wound resistors and electrolytic vs ceramic vs tantalum capacitors.