A good strategy?

[AlbusMalum]

How good is the "civilian structure strategy"?

[MoiMagnus]

How good is the "civilian structure strategy"?

Taking blue cards in Age III is good. It's both more points for you and less points for the others. (While for example, if you go science, taking a green card is more point for you, but that card was probably useless to most other players)

However, in Age II, I'd say green and red are much more important. You absolutely want to avoid someone getting military victories for "cheap" since winning wars is worth up 24 points (from -6 to +18), and Age II red are the best red in cost/efficiency ratio. Similarly, Age II is the age where players going for green actually have to commit to it.
=> Chances are that building your wonder is actually better than playing blue cards, as it allows you to deny important cards to others.

Admittedly, blue cards are never bad. But I wouldn't consider them to be a "strategy" alone. You will sometimes end up spamming blue cards and winning, because it happened to be the optimal play with your given hands. But this is opportunistic, not strategic.