Early war I think is very viable with BNW, but it does require much more planning and decision making than with Vanilla or G&K.
@OP - For your situation, avoidance of the problem in your current game is out of the question... since the cities have already been captured. Getting out of the situation is going to take some time, but there are some things you can do in the short term to try and mitigate the issue.
* Trade away extra luxuries. Since your happiness is so low, your first priority should be to trade for other luxuries that you don't have. Failing that, trade for gold per turn. It's robbery, but even 1gpt right now will help but you should be able to get at least 3 even from a civ that doesn't like you. I've not gotten more than 5.
* Remove unneeded roads around the cities you have just captured. If the cities are more than 5 tiles away from your empire then the amount of money you're making on connected routes is probably not even paying the maintenance cost of the roads right now.
* Delete extra units. If you're not going back to war any time soon, delete units not absolutely necessary for defense (starting with those that don't have any promotions yet). Another often overlooked place to cut back on unit maintenance is extra workers; at least until your economy has recovered a bit... but it's a good idea to use extra workers to remove excess roads before you delete them. Also be sure that you only delete units within your borders so that you get some cash from them.
* Possibly consider selling or trading away one or more of the cities you just got to another AI. A city that doesn't have a new luxury probably isn't worth keeping.
For future games, simply being aware now of the consequences that war can bring you will already help alot. Before you capture a city make sure it has something of use to you, make sure that your empire can support the weight of adding another city too. Capture fewer enemy cities.
This statement is a fantastic summary.
Early war is quite viable.
Expansion is quite viable.
The combination of the two.... MUCH more complicated.
@OP - For your situation, avoidance of the problem in your current game is out of the question... since the cities have already been captured. Getting out of the situation is going to take some time, but there are some things you can do in the short term to try and mitigate the issue.
* Trade away extra luxuries. Since your happiness is so low, your first priority should be to trade for other luxuries that you don't have. Failing that, trade for gold per turn. It's robbery, but even 1gpt right now will help but you should be able to get at least 3 even from a civ that doesn't like you. I've not gotten more than 5.
* Remove unneeded roads around the cities you have just captured. If the cities are more than 5 tiles away from your empire then the amount of money you're making on connected routes is probably not even paying the maintenance cost of the roads right now.
* Delete extra units. If you're not going back to war any time soon, delete units not absolutely necessary for defense (starting with those that don't have any promotions yet). Another often overlooked place to cut back on unit maintenance is extra workers; at least until your economy has recovered a bit... but it's a good idea to use extra workers to remove excess roads before you delete them. Also be sure that you only delete units within your borders so that you get some cash from them.
* Possibly consider selling or trading away one or more of the cities you just got to another AI. A city that doesn't have a new luxury probably isn't worth keeping.
For future games, simply being aware now of the consequences that war can bring you will already help alot. Before you capture a city make sure it has something of use to you, make sure that your empire can support the weight of adding another city too. Capture fewer enemy cities.
The mechanisms of the game don't allow for early war to be feasible when combined with your own expansion.
This statement is a fantastic summary.
Early war is quite viable.
Expansion is quite viable.
The combination of the two.... MUCH more complicated.