Not particularly thrilled with it in MP. Though it's more to do with an overall lack of resources and the absurd retraining times in late game than the building itself. Seems at some point our townfolk would have invented assembly lines and later, automation.
Now imagine how much fun the next age will be? Attacking gold walled atomic bases with level 3 silos, two dozen traps, and if you're really lucky, Hold the Gates for enlightenment age loot? Meanwhile upgrades will run between 13-17,000,000 gold/food or roughly 280,000 oil. Wheeeeee!
Granted, who knows if/when that will be, but without a fundamental change in offensive power, raiding mechanics, training times or resource production it's likely what we'll be looking at. A separation of multiplayer and war defenses would work too, though I haven't the foggiest how they'd go about it.
Ehh. In for a penny, in for a pound at this point. Just not sure how often I'll be in.