I think I manage to get the "early rush" to work in 2 out of 5 games, depending on how far away my neighbors are and if they choose to build walls or cities on hills (and they do if they're Protective). If I can't get the early rush to work, I am pretty much screwed.
In BtS it rarely makes sense, IMO to "early rush" because the AIs don't REX like they do in Warlords. In fact, in BtS it makes much more sense to REX, yourself, and then protect and support all the cities with a careful balance of military and economic power.
In Warlords, IMO, it *SOMETIMES* makes sense to early rush, but not always. As you said, it depends on the situation. If they've REXed over most of the "goodies", the luxury resources, the gold, even some needed military resources, and they're crowding their cities close to your capitol, it's a no-brainer, rush early and often. Axemen, Axemen, and more Axemen, and ignore everything else until you get you some GROUND to pound a little later on. But sometimes even in Warlords they leave you an opening to peacefully grab the better-quality land, especially if it's one of those slow-expanding AIs that prefer to build something useless like Stonehenge before they even get their second city built. In that scenario, you need to balance the axemen with settlers, and REX into the land yourself, and then get some workers to cottage up the commerce cities (sorry SE fanatics, cover your eyes here), just to get enough gold coming in to support the maintenance of all those cities. A beeline to Code of Laws and Currency helps with that support as well. In that scenario, you still do have at least one city building all-units, all the time, but that's just to prop up DEFENSES. Against barbarians, and AIs that are Aggressive like Alexander. Especially Alexander because in my experience his trigger for an early rush is the thinnest I've seen, even thinner than Monty's. "You have furs and I don't, WAR time!!!" Or so I imagine him saying...
I think I am now stuck in "aggressive" mode, as I can't really see myself winning unless I kill or wound my neighbors enough so that they can never hurt me back. And I haven't been having much luck in the past few days, either, which is why I haven't posted much. Do you think getting Beyond the Sword would just aggravate me to the point of giving up on Civ?
Well, I think BtS requires a balance of aggression with adept domestic management and foreign diplomacy. Warlords does tip the balance a *little* bit in favor of the aggressive approach, moreso than BtS, so if you think aggression is the only aspect of the game you're skilled at, then you might want to stick with Warlords a while longer.
Plus there are some changes in BtS that I absolutely detest, hate with a passion, and... then hate some more. You will come to seethe with rage when you get prompted to vote for a leader of the Apostolic Palace, for example. Prepare your blood vessels to resist bursting, trust me. The U.N. in Warlords is absolutely toothless and meaningless compared to this one: they can command you to stop a war against one of the members, for example, and if you defy the verdict you get a -5 unhappy hit in all cities with that religion, for what *seems* like... forever. (Prolly 10 turns, but it's 10 turns of HELL!) What that means is that war just slows to a crawl, and if you're LUCKY you get one city taken before an Apostolic member appeals to the Pope for a peace treaty... again.
Also, in BtS, siege engines suck. They really do. It now takes forever to bombard city walls, and while defenders can eliminate your catapults, your catapults can only *partially* damage defenders. Sure that may make defense easier when an AI invades, such that only an idiot really would lose a city in BtS if he reacts in time with enough Longbowmen and such, but... the price to pay for it is sky high when on offense.
All in all, wars in BtS tend to stagnate more, and get nowhere fast, for either side. This is what Firaxis calls "balance". ::spits::
But, on the flipside, some of the new concepts of BtS have grown on me: Moai Statues can make a mostly-water-tile city become nice and productive with a +1 hammer per water tile bonus, and makes said city a really good candidate for a second military city, which means on Continents you can consider putting West Point in a high-hammers landlocked city, and just settle some GGs and build a generic military academy in the Moai city, for your "Anapolis", your naval center. And later on you can use Red Cross as your second National Wonder there, such that all ships get build with Medic 1, which really comes in handy when worn down with damage in foreign waters: pop into a discreete icy bay, heal the damage, and back into the enemy waters to destroy ships, etc.
Another one I like is the Levee building, river tiles +1 hammer... a few tweaks like that here and there add just enough "sugar" to BtS to make me lean against going back to Warlords. Just enough... barely.
Anyway, if the aggression approach seems to be a problem for you (and you say it only works for you 2 out of 5 times?) then maybe the rules under BtS might help your game results, rather than hinder. IMO.