Optimized as well as I could. Might not be much different if you pulled the lower stacks off the steps and placed on the next level up...but it held pretty well as is. Traps control the North and West pretty well all on their own, if you want to adjust the build, you could probly safely drop the portion of build up there and focus on optimizing the South half. The trouble is the Far East side. Ruthless has a slow ogre issue and no weapons, so I wouldn't recommend it.
This build could probably work fine for campaign even (though you might find simpler builds out there), but if doing campaign I'd use more minions to fully block off the steps on the South.
I'll test it on Ruthless soon.
Party: 1 TB monk, 3 summoners with huntress/monk pets
1 summoner at each hint 1,2,3
Hint 4: It can help on Ruthless to block this off with minions, just throw some orcs and archers in there.
Hint 5: TB stands here to boost all the defenses, if you have terrain piercing shots, can face the arrow direction and get mana, tends to go on cooldown about half way through.