The truth is that any team comp can be a very viable strategy, but unbalanced comps tend to be the result of immature CNE efforts. Balance and coordination are the sign of mature - and successful - programs. You may find advanced teams using primitive toolchains and simple strategies to great success because they've built a program with the proper team composition.
People (including me on this blog!) like to measure adversary programs by the sophistication of their tools. But what true teams have is rapid turnaround on exploits, completely unique implants, and massively creative sustain while inside. They take every small advantage - every tiny mistake the defenders make - and turn it into domain admin.