What is the knowledge issue in this problem:" Is it more important to discover new ways of thinking about what is already known or to discover new data or facts?"
Remember first that a knowledge issue is any issue about knowledge about how we get it, how we process it, how we categorize it. There could be a number of knowledge issues that we could get out of this problem. Some might be open-ended and some might be more closed.
For example, a relatively easy and closed-ended question might be "can we think in new ways about existing facts?" From there, you could move to a much more open-ended question. That is "how can we know that we are in fact thinking in new ways?"
Alternatively, we can look at a different part of the problem. We can ask "what is important?" We must know what is important in order to answer the question, but do we know this? How can we know what is important?
Finally, we might ask a question about acquiring the answer to the question as a whole. We might ask "how can we measure the results of thinking in new ways and getting new data?" In order to answer the question as a whole, we need to figure out what comes out of thinking in new ways and what comes out of getting new data and we have to compare those results. So how do we measure the results anyway?
All of these would be knowledge issues about this general question.