About the war with America I have a slightly different view. Since I haven't played that many games in emperor yet I was mainly worried AI's getting cities all over me and then ganking up on me. Capturing the workers probably wasn't worth it if you consider purely my situation in the global comparison. But for me it was just about setting America back few years to be able to get decently big core before they can claim big chunk of territory.
Maybe they will give me couple of techs in peacenegotiations(probably not)
Let me add some ideas to this topic as well. I agree, your reasoning is quite ok and such a strategy may yield good results. To put it onto a "generalized level": this is again the usual conflict between two opposing strategies, each of which may be quite valid in its own right.
- Should I build some early military (at the cost of under-developed infrastructure and growth) and then whack 1-2 nearby neighbors, before they get too strong?
- Or should I concentrate on my sound development first, get a lead over the neighbors that way and then conquer them with my bigger power?
However, if you fall too far behind by the early military adventure and if there are other nations that were able to develop peacefully (e.g. on another continent), you may be hopelessly behind by the time you meet them, and building a necessary invasion force will take much longer with your under-developed core, so they will be much stronger by the time you get to attacking them.
So on continents I prefer building a solid foundation first, and attacking later. As long as there is still enough land, it is much easier to expand by building a settler than by building enough military to capture a town and to defend against the counter attack. (Especially as we have a quite food rich start here and can crank out settlers easily.)
Also the early solid core will be useful for both tasks: conquering direct neighbors as well as preparing an invasion on another continent quickly. An early military build-up is useful only for the first task.
Looking at this particular case again, the early attack on America may not have been so bad after all. Looks like you got away with it without having to invest too many resources into the war (1-2 warriors, I think), so your development is not particularly delayed because of the attack, while the Americans are indeed quite cripled now: 2 workers lost and hemmed in at the choke-point. Once you have 4-5 Gallic Swords ready, you will probably take them out easily.
(The only slight drawback will be that the Americans will not have built many towns by the time you capture them. You are trying to prevent them from building many towns. I on the other hand like them to build as many as they can, because then I don't need to build them and can later, when I go over to the offensive, reach domination much faster...

It would really be interesting to compare your approach here (early weakening of the Americans) with the one in my game (let them develop undisturbedly, meanwhile develop as well and then take them over with superior forces) and see which one succeeds in taking over our continent (and having it developed!) faster. Unfortunately we can't get meaningful results from the comparison, because even if the early crippling approach in your game is better, the more powerful capital location of my game would probably more than compensate for it. In order to be able to really compare apples with apples here, you would need to settle the capital on the river and then try the early sneak attack on the Americans?!
