Infernal Mage was at actually at 8; Dark Knights was actually at 12.
Shadow Archers: 10
Orc Warriors Den: 8
Infernal Mage: 8
Goblin Rocket Riders: 10
Dark Knights: 13 (+1) There are just so many reasons to upvote these guys. Take a look at their names and have a chuckle.
Melting Furnace: 10
Specters Mausoleum: 4
Goblirangs: 10
Bone Flingers: 11
Elite Harassers: 10
Orc Shaman: 10
Grim Cemetery: 10
Rotten Forest: 6
Blazing Gem: 11
Deep Devil’s Reef: 10
Wicked Sisters: 8 (-2) I haven't ever found them particularly useful. The other mages fulfill pretty much everything this thing does except they're better at it. The range is its only notable utility, but even then Orc Shamans almost have enough range to size up in that area as well (not as big of a range, but high range plus a better tower).
Goblin War Zeppelin: 11