I would like to say that any Bible study is good, but that is surely a stretch. In spite of us, God can and indeed does use his written word.
One of my complaints about what can happen in Bible studies is the failure to really consider well a passage in its immediate context, as well as general context. This is particularly challenging if not nearly impossible to do in a topical study, though I think a topical study done well, I mean really sticking to the topic, can do alright in this regard.
Scripture passages are not holy dust, simply to be read so as to give light to our days. That is where I think precious promise books, which quote Bible verses and perhaps short passages are limited. Not that they can’t be a blessing and do much good. And I’ll add that note even in regard to the type of Bible studies I’m complaining about. Again, God does use his word, often in spite of our failure to handle it accurately. However we still have the responsibility before God to work hard at handling scripture accurately (2 Timothy 2:15).
Context matters. And we might say that the point of every passage is the good news in Jesus, or perhaps better put, that is the plot of the story we’re reading, the rest of it, including teaching material such as Proverbs, etc., filling in the details, since this is to be lived out in real life. Remembering too, Jesus words, that all the law and the prophets hang on two commandments: to love God with all our being and doing, and to love our neighbor as ourselves (Matthew 22).
That is why my own preference, when leading a Bible study, is to settle down in one passage. I will try to share the context of the passage, and then guide us in a discussion which lends plenty of freedom for people to think and share preferably in relation to the passage. Each passage has so much in it, the topic at hand or the main points are so compelling, that there is no shortage to stimulate us in our thinking, and hopefully from that in our praying and living, to the glory of God in and through Christ.