I only managed to run one game of Leverage at PAX, and despite my degraded health, I think it went decently well. I've found I like paying a lot of attention to what the group takes as their secondary role, since it often tells you a lot about what the group is really like. In this case, we had a lot of Hitter, with the non-violent Thief in the leadership role. The mastermind was the political guy, a former lawyer, and he did a great job with it, and at the same time underscored something that I've been doing to help out Masterminds.
See, a generic Mastermind is a little bit rough to really engage in play. It's so open ended that unless you have a player who likes to scheme purely for the sake of scheming, the Mastermind can be left at something of a loose end. He can do things, certainly, but they're not necessarily things that will distinguish him from the rest of the crew. Worse, the fact that he could do almost anything introduces a degree of option-induced paralysis.
To this end, I've started treating the Mastermind as something of a specialist - the Mastermind picks some arena of expertise, and within that, I just treat his knowledge as absolute. Nate Ford, for example, knows insurance in and out, which extends to things being insured. Other Masterminds might know taxes, high finance, the law or some other professional pursuits. Specialties might also be more abstract, like "being the guy who knows everyone" or the like - so long as the idea is very clear, then its probably workable.
This ends up making very little mechanical difference. Leverage characters are already awesome, and putting a a bit of spin on the awesome doesn't actually shake up the table much. But what it does do is give the table a much stronger sense of what the Mastermind's role is and how he contributes to the team. For the Mastermind's player, it imposes fruitful limitations. Because the Mastermind has a clear strength, when in doubt, he knows he can play to it. It gives a lens to look at problems through, and that can be utterly invaluable. For the GM, it also makes it a lot clearer when Mastermind is the right thing to be rolled. Lastly, it has the thematic effect of giving the Mastermind a stronger connection to "the real world", and given the source material, I think that's pretty cool.
It's a small thing, and like most good Leverage tricks it's a bit of a con, but I put it out there for others who might find themselves in a similar situation.