What an interesting subject, the main strength of our teams...
My crew was established in June of 2015 and I have been a member from week 3 and forward. In 2016, I led my team all year until I finally passed the throne to a newer up-coming player of mine, Ike bagnarok, who in all his time as Leader, has done a better job than I could have hoped for.
Building a strong and successful team is, largely, is a group effort and takes serious commitment and fluent communication from everyone. Above that though, the Leader's intelligence, relevant skill sets (people skills, organizational skills, problem-solving, team management, etc...), determination to "win", dedication of time and money, stance on morals/values, and level of interest in the game.
(It's interesting actually, you can often see a Leader's personality or attitudes throughout his, or her, entire brotherhood. Like minds tend to gravitate towards each other. These teams are like social cliques in the more developed servers.)
I would agree 100% that (in any good BH) the Leader is half the strength of the entire team, if not more. Leaders are the ones monitoring their entire team, what's going on in the game server, making communications and plans, testing out strategies, and dedicating generous amounts of time (and money!) to the game. Running a strong team on a developed server in a game like ours isn't something anyone can do. You have to have the right stuff if you want to achieve, and maintain, a position in the top 100 brotherhoods.
Ike bagnarok is the main strength of Rat Basterds. He is our driving force.
Of course, the Rats wouldn't be the same without ol' dear Luna to stir the pot.