As much as I hate to be the anonymous jerk on the internet who gives unsolicited DMing advice to Ross, I do have to say one thing: Ross, your 4E combats suck.
I love the character interactions. I love the subplots. I love the breadth and depth of the world you guys have created. Its all gold.
But the combats suck, dude.
Chief problem, as far as I can tell, is that you've fallen into the fallacy that states that Roleplaying and Combat are separated by some sort of force field that keeps them from interacting. This is Thought Crime, especially when it comes to a combat-and-heroics laden game like D&D 4th Edition. You want to create imagery, provide dynamic set pieces, and encourage your players to be just as creative with their Awesome Stunts (or Laughable Failures) as they are with the talkier scenes where they make power plays and try to get virtually laid. Also, your monsters and PCs CAN talk when they're beating on each other. Smack talk and dumb monologues and so on may be hoary cliches, but they're FUN ones and can go a long way to engaging your blabby players.
Now, I'll admit; getting more flavor into your combat can be a bitch when you've got a big group. I also know how Imagination Fatigue can set in after you've all spent hours already trying to be witty, clever, and creative. Sometimes the mechanics can also get in the way - though I think 4E does this less than older versions of D&D did. I also know you guys can do better, though, based on other APs. You have no end of talent and sources of inspiration to draw from. You just need to find a way to keep that invention from disappearing when Initiative rolled and Hit Points are tracked.
