The very reason to have E-Discovery is either to convict a person of a crime, or to defend the company from an allegation. The result of the E-Discovery shall then be presented in court or in a Domestic Inquiry session.
E-Discovery is not a service that shall be taken lightly. It must be done by following the right process. Simply having a staff with vast knowledge in IT is insufficient. E-Discovery is a combination branch of IT and legal knowledge and skill. Staff must have both knowledge and skill. Any flaws in conducting the E-Discovery can easily be picked up by the other opponent. If this happen, then effort to develop own E-Discovery seems pointless.
Interesting points raised by Eric Shirk1 published in American Bar Association website is that there are major risks involved with do-it-yourself approach. The following table summaries his points.