I agree, on where the flaws often make the games.

My example of that was Heroes of Might and Magic 2 vs 3. 3 is the legendary one that everybody remembers, but I actually liked 2 better. Sure, 3 is far superior for balance and AI and content... but for me, the unbalance of 2 was its charm. Trying to win with the underpowered knight castle, or against a far superior force with tactics like the blind spell that the AI wouldn't counter... that was the fun of the more primitive Heroes 2 and wasn't quite the same in the more developed 3. Less development in a game can actually make for more fun factor.