I believe the main role of a CIO is to bring new technologies to a company that are aligned with the companies mission. As technologies evolve, the company has to as well. I think the best way to balance the tradeoff of training and additional technology would be to evaluate the risks. The evolutionary nature of technology makes staying ahead a top priority. In doing so, you mitigate risk, but training employees to learn every new technology is a waste of time and resources. The best course of action is to evaluate the potential risks within the systems already in place, and evolve only when necessary. I would only push to expand if it were absolutely necessary for the companies mission, or if there were too many new risks with the current system.