In addition to the "toggle follow key" and "drag select" suggestion, I think that a great benefit would be a formation key as alternative to the default blob that's far more susceptible to the pathfinding's whims.
So basically the very same BG2/PoE/Pathfinder system inspired by RTS that we all are asking for. It already does all these things rather intuitively. Larian's system is a textbook case of a "solution" in search of a problem to solve that never existed.