What changes would you make if you came on board?
In order to be able to answer this question, you need to have done some prior research about the company, the department, and the position that you are applying for. There is no way that you can answer this question on the spot without any prior preparation. If you do try, it will be painfully clear to the interviewer, and will only count against you.
Under no circumstance, should your answer be nothing. You can kiss the job goodbye if it is. Everything can be improved upon, and in asking this question the interviewer wants to see two things. One, if you have done your research about the company, and second, if you are creative or innovative enough to come up with new ideas and solutions.
Hence, you should know something about the company and what they are doing in the market. Have an answer ready with you in case you are asked this question. It doesn’t need to be groundbreaking, but you need to be able to show that you know about the company and its practices, as well as some of the current work it is doing, and how you will be a great addition to the team.
Just keep one or two points on hand and ready to talk about, as well as why you think your idea should be implemented and how it will help the company. It is okay to give some broad generic answers, by claiming the fact that you don’t have much information on the projects, after all these projects are possibly confidential. But be sure to give some sort of answer that proves your credibility.
However, be careful not to overstep your bounds. You don’t want to come across as someone who thinks they know better that an entire company put together. The idea here is to just show that you are capable of decent ideas, hence proving that you would be a valuable addition to the team.
While most of your projects are confidential, from what I could find out about the company, there are some aspects on which I think the company can improve on. In my opinion, it would be beneficial if Product X would be reintroduced into Market Y, with certain changes. However, of course I don’t have all the details on the market, the product, or the research that the company is bound to have done. Hence, there is probably a reason why the company hasn’t done that.