I disagree entirely with it being a weaker strategy, while your points are sound, there are far deeper reasons for it to be effective.
- When you've got 10 players, with 10 villages, it's 10 different accounts, attacking at 10 different times, forcing defensive maneuvers throughout the day, not just at set times. In this game, you get to choose when you attack, but you don't get to choose when you defend, and the person who is the most over worked on defense, is often the first one to quit.
- defensive tribes rarely last late game, because of their slow progress, they end up quitting before the end.. This is a game of attrition, while defense is necessary, the one who is playing the more enjoyable game, generally sticks around the longest.
- a person who takes losses on a frontline, when interwoven (as you call it), takes minimal losses of a few villages, and you can re-draw a line to stop the onslaught, and stack it back up. The single player takes massive losses if they don't hold, often setting them back to the point where they don't often want to continue on. Again, it's a game of attrition.
- having 10 players in the area means you have 10 chances for a person to log on to be able to send support if you are under attack, while being a person with a big cluster means you can only rely on your own support. The chances are when you are being attacked as the only person on the front, all your villages are getting bombarded, which means a lot of dodging, and its difficult to have the defense at home. More often than not, when there are 10 people ont hat frontline, a tribe will pick on 2-3 of them only, leaving 7 others free to shuffle their D around.
The biggest draw back to being interwoven is that a tribe needs to act, and function as one, but if a tribe can do that, it can be a fairly dominating strategy that keeps players interested in the game far longer, as they've always got something to do, and rarely take huge losses when at war. I personally feel that a tribe who does work and act as one often, are more likely to play it out to the end.