(Prompted by "Leadership Auras" thread)

I'm thinking of different ways to add "firepower" to a villain group in a battle. We all understand the convention of adding a tougher MOB type to the mix as a boss/lieutenant that is harder to take down, and even allowing that NPC to increase certain stats of the minions around them. I'm not talking about a huge change to game mechanics, just some ideas to help the DEVS when brainstorming this kind of thing

How about, instead of an obviously different and additional NPC we see more of a synergistic behavior emerge from the minions with maybe an additional visual clue? CoH had Sky Raiders and you would occasionally encounter a mini-flyer in a fight that was essentially just a big NPC. That's OK, too but I'm thinking more along the lines of a "crew-served" weapon that would change the flavor of the fight. Something that might require the attention of a few of the NPCs to operate, but adds an overall more dangerous element to the mix and changes how the minions fight while it is present.

- Tripod machine gun/laser blaster/sonic disruptor/etc

- Single-facing (wall) force-field generator

- hovering chopper w/sniper

- tank

- suitcase bomb (counts down and does damage over a wide area)

You get the idea. From a programming mechanic standpoint, I can see how these would probably be considered additional "character types." I'm just looking to shift focus/tactics without just adding another "thing to beat up." Maybe it just exists for a short duration, or it only comes out when the mob group hits half-strength, etc.

Any better ideas than my little list above?