According to this CIO report there is nothing wrong with deploying a light set of features sooner, so you can start the ball rolling for user adoption. This in-depth advice article offers tips and direction for heading down the right paths to expanded CRM functionality.
"Free / Open Source Plug-Ins: Every CRM vendor develops an ecosystem of developers around them, and the health of this ecosystem is important to you even if you never intend to use the free stuff. More dynamic ecosystems mean a bigger pool of developer and administrator talent. These will be important to your project staffing, whether you plan to use consultants or hire.
"For sheer numbers, Salesforce.com has the strongest set of freebies, with functionality ranging from simple templates to complete applications. They wrote about half of their free/open source add-ons themselves -- a considerable achievement. Beyond numbers, you need to evaluate the user feedback scores (hopefully, there's a 'star' system) and how recently the plug-in has been updated. Since even the most robust CRM platforms evolve, it's important to see how actively the community is keeping the freebies up to date."