1) So I have a unit of 30 goblins, including full command, two cheap Big Bosses and a Shaman.
The unit is ranked 5 wide, so one character must go into the second rank.
The Shaman does this.

Here's the interesting bit:

2) There is no longer a rule that puts the Shaman "semi-out of the game" if he's in the second rank, thus he can still fight (like a goblin), use magic items and cast spells.
However, he cannot be attacked back or singled out with shooting.
The shaman is modeled standing on a big mushroom, thus he can draw line of sight over the heads of the other goblins (convenient for magic missiles and other spells requiring line of sight).

3) Profit?