Most people will respond to this question with an emphatic "YES!" And I would concur with this statement to a large degree. However, I would argue that saying "yes" is quite an incomplete response.
There are so many facets to interoperability. Two of the main facets include: 1) how our crisis management structures work together, and 2) how our technical systems for data and information sharing communicate.
But before we get to making these two facets compatible, we must balance the need for information with the availability of that information. We need to define the types of information we truly need to respond in order to better prioritize progress on interoperability. We can just say we are going to make everything "interoperable." In reality, interoperability is quite a large subject and with many many micro-issues.
Often, we first ask the question: "What data/information is available?" However, to obtain better data and information, we need to start with the question: "What data/information do we need?" This helps guide design and development toward the most impactful milestones.
As we approach big data, this will become even more important as we have to process and make sense of the massive amounts of information that will become available to us. Ultimately, we may have the great majority of data we asked for; but if 50% is not useful, we just wasted a lot of critical time and effort sifting through it all.