I've been involved in CRM consulting and solution implementation for 15 years now, and other business software solutions for many years prior to that. Over those many years and projects, one of the more important bits of knowledge I've acquired is that no *good* solution is ever finished, rather the good solutions are continually refined and improved.
It probably seems obvious that businesses and the marketplaces that they serve continuously change and evolve, but when you are deeply involved in a software solution implementation - particularly an initial implementation of a large system - it can be easy to loose sight of the fact that any given part of the hard work, data migration and cleansing, customization, training and documentation, etc. can very easily become unneeded or unused in the not so distant future for any number of reasons.
During non-trivial implementation projects, it can be very easy to fall into the trap of thinking that whatever solution you come up with must be absolutely perfect and all encompassing because it will be in place for a very long time (i.e... This solution is the final destination). This line of reasoning often leads to overly complicated solutions that take longer than desired to implement. I've also found that requirements from end user and business representatives also tend to be overly complex and overly encompassing when the business people feel like there is only one chance to get the desired functionality defined and implemented.
I find it often helps to occasionally remind the project team and the business sponsors that while we are seeking to create the best solution possible, we should also acknowledge that things will change with the way the business conducts itself, what the marketplace demands, and how technologies emerge and evolve We should acknowledge that we will not all of our customizations will be the very best fit on our first try, but that we will continually review, refine and evolve the features in conjunction with the business sponsors and users. This shift in perspective often greatly simplifies requirements, results in less defensive posturing by all parties involved, and leads to a more team work oriented environment,
So remind your project team to embrace the journey and continually look toward that ever changing destination - for that is one of the many subtle secrets to CRM success.