I have come across many people who talk about IT systems becoming too complex with too many moving parts. I believe that this is usually an excuse for lack of Experience / Expertise.
Think about the first time you drove a car...did it seem simple or complex ? Obviously it was complex, but once you gained experience it became easier and now you can do it without really thinking about it (assuming you have a driving licence!).
It is the same with IT, each time you have to install a new component it is going to seem complex and for sure you don’t want to install components just for the sake of it (This is why you need an architecture)...but don’t expect it to be easy the first time you do it.
This “complexity” debate reaches fever pitch with respect to SOA in many organisations as the number of systems/concepts/standards that need to be adopted becomes very high. For many the learning curve involved is just too steep to cope with at the same time as “doing the day job”. I believe this is a real inhibitor to the mass adoption of SOA - and may even kill many DIY SOA projects...