For a true enterprise solution (user based exceeds 1000), can this be effective with a single instance? My experience is that users get very frustrated with default issue searches that include all of the hundreds of projects that cross many lines of business and programs. The only practical methods I see to limit the default scope of searches is to create many JIRA Categories, and at least the user can find the correct JIRA Project(s) to access. However, it still requires JQL to limit searches to a meaningful subset of JIRA Projects.
It appears to me, the only practical approach is to generate multiple JIRA Instances. Is this true?