The developers of integration applications are often people whose primary expertise is not in programming but rather in the processes being automated. This is problematic because middleware applications often come with user intrafces that are difficult for programmers and professionals to work with.
Not all middleware fits the standard applications, networks, and systems management product suites.
This can make QA and debugging more complex. These difficulties, but even they often require work arounds.
Unlike major database and development tools, many middleware packages are not updated in predictable cycles, integration application typically incorporate business rules that change constantly.