One of the problems with custom development is that no matter how good the requirements are up front, it is hard to anticipate every situation when the app goes into production.  The benefit of a commercial application, should be, that over time the broader user community puts it through its paces and exposes what is really required.  Every collaboration process, no matter how simple, has many ramifications even if the process itself is defined as simple.  We recently delivered an application for reviewing training matrixes.  These are spreadsheets that define processes within a manufacturing company.  They needed to be reviewed every 90 days.  Sounds simple.  10 days before the review is due, an email needs to be sent.  This is a requirement for the ISO QMS certification.
Our Docova web based document mgt system has workflow capability and a review policy feature whereby you can flag documents that need review on a regular basis.  It looked like it would work out of the box.  We had put a lot of thought into the design of the review policies and we had features such as escalations that would flag people if the review did not happen as it should.  In this situation, the customer had the requirement that revisions are tracked.  Not a problem, we have full version control too.  A couple of issues that came out when we looked at this more carefully was that the review policy needed to act on only the current version of the training matrix, not the past revisions.  That looks like a small change but when you take into account the workflow that has to happen before the new revision is approved, the ability to retract releases, promote past releases, change document ownership as resources change, and take into account the security model through all of this  it turns out to be pretty complex.  Docova benefits from this experience, and just keeps getting better and better.   I am amazed that some document management products claim that they do things like version control, but they are so limited in capability that they could never work in a production environment.  Making a copy of a document with VER added to the document name is not version control.    I am starting to believe that there are no simple processes out there.  If someone says the process is simple, chances are they have not thought it out carefully.