Of the major CRM vendors, only salesforce.com and (at least aspirationally) SugarCRM use Agile teams to deliver their product. You really see it in the delivery schedule: new features show up at least three times a year. You also see it in the feature lists, which may look meager if you review a single release in isolation. Major functional enhancements are delivered incrementally, spanning two releases or more. In contrast, the traditional waterfall deliveries of Oracle, Microsoft, and SAP mean you'll see a larger feature set delivered in widely-spaced releases. While the traditional model provides lovely multi-year feature roadmaps, anybody who's been around for a while knows that the projected dates are almost always wishful thinking. Worse, the big-bang model does not have deep user-centered design baked in, so the user interfaces initially delivered in the waterfall model can be real impediments to end-user adoption.
Coming back to the KISSS principle, for CRM vendors it;s more than just a matter of delivery schedule. The ability to deliver "separable" -- highly modular -- features depends upon the architecture of the CRM system. Just because the product is written in Java or C# doesn't mean that it'll be easy to interface with or extend. If the foundation is 1M lines of code and 200 highly intertwined tables, it'll be much harder to write good extensions and flexible integrations. Instead, you want to see clean, consistent call-in and call-out exposure of all important system methods via Web services or RESTful APIs that don't require10 levels of pointer-chasing to get to an object. Also, make sure that new APIs (and supporting documentation) are delivered more or less simultaneously with the CRM features they apply to. Check developer forums/discussion groups for indications of the scope and quality of the APIs and the documentation that comes with them. Even the best vendors have small gaps and errors in their docs, but you don't want your developers having to discover API behaviors through months of trial-and-error. This is a movie we've all seen too often.
The KISSS principle definitely applies to your vendors, your integrators...and your own project teams.
David Taber is the author of the new Prentice Hall book, "Salesforce.com Secrets of Success" and is the CEO of SalesLogistix, a certified Salesforce.com consultancy focused on business process improvement through use of CRM systems. SalesLogistix clients are in North America, Europe, Israel, and India, and David has over 25 years experience in high tech, including 10 years at the VP level or above.