^Agreed, Philosophy can fill large gaps and is extremely useful (pacifism and Taoism), Drama is also extremely useful and can be traded for huge sums of money (Ai never has it even on emperor and doesn't value it so i generally don't get useful techs out of this). Literature is also a good moneymaker once the great library has been built or is near completion. Code of laws is also a useful tech and also makes money or can ocassionally be traded for something really good.
MC is also useful for trading. This tech is fairly useless otherwise except for the ability to get GE points. These tend to get drowned in GS points however unless you're very focused to get the GE. I would not go for this tech unless i got it through the Oracle.
I used to go for monarcy in earlier games for the happiness but i try to solve this problem with drama nowadays. Monarchy isn't a good trade tech at all, same goes for feudalism. The Ai puts emphasis on these techs so most of them usually have it by the time you (want to) get there.
Civil service is a double edged sword imo. you can get a lot out trading this tech but it speeds up the Ai no end, same goes for paper this doesn't speed up the Ai but trading this tech risks losing the liberalism race.
While for human SE players Philosophy is very important i have the feeling that the ai doesn't do very much with it(converting to pacifism for instance), same thing with drama and Col. I might be quite wrong here, difficult to look behind the ai screens.
