This is a good post on the systemic drivers of complex processes, take the time to read the whole post. I have a bias is against off the shelf software as it often ends up forcing the process to be designed around the software. And with the amazing power and relative ease of web based applications creating solutions that are specifically designed to the organization are often relatively easy. And yet, as indicated in this article there is often a strong bias in the other direction for buying off the shelf software because it is cheaper and/or faster.
Of course, the decision in each case must be weighed to determine the benefits and cost of the various alternatives. Just remember, if you decide you want simple and flexible, to have your decisions reflect that. I enjoy a telling quote from a software vendor on Toyota’s IT expectations: “it demands that the software or technology be flexible and adapt, often by customizing the code, to its business processes, and not the other way around.” They are right.