[rdonj]

In SP I would be very hard-pressed to take an SC pretender. You're right, usually the magic diversity and gem income are much better. And even on impossible difficulty, it's quite possible for most nations to compete effectively with the AI without an awake SC. In my opinion those are more useful for competitive MP games, where provinces are at a minimum and rush deterrent may be more valuable than long term diversity and power, especially if that SC allows you to make a quick land grab on an opponent's territory.

Personally though I dislike awake SCs for much the same reasons you do, and I would never take one unless with a nation that I just didn't feel needed anything else, or was so weak early game that I had no other choice (i.e. the alugra mod in SP, which I've finally given up on trying to make work without one).