External agents have played important roles in defining the governance agenda we all speak about. IMF staffers in their men in black suits stand out the most. World Bank specialists sometimes try to blend in with less formal attire and a more 'I'm one of you' approach (count me as one of these). They also end up sitting at the other side of the bargaining table when work heats up, though.
External agents are most likely to influence change on the inside when their ideas reflect those of the insiders. External agents do not have the authority to introduce change. Their influence depends on whether they are able to use their status to persuade insiders with authority that their ideas make sense. Many of us may have status and good ideas, but we do not have authority to change the organizations, governments and countries we work in. It matters that we are we and they are they. We are not them. And they are more important to change than us.