I am at the end of the Middle ages with Navigation, Economy, and Democracy to go.
Why are you researching optional techs? If you really want them, trade with the AI for them when the cost has gone down or get them as part of a peace treaty.
Should I trade resources/luxories I own for techs, or should I go with gpt?
Like most answers in Civ...it depends. You don't want to make the AI too happy...they tend to build entertainers which can be put back to work building things if they're happy. The AI doesn't use the lux slider. Trading resources or techs may allow them to build more modern units...bad if they're your neighbor about to attack, but good if they are far away and bankrupt themselves with unit support.
Should I just wait for democrocy? What is the advantages/disadvantages of Democracy vs Republic?
I'd go to Republic and stay there. Demo is slightly better in lower corruption and faster worker speed, but Republic is still very good and gets better speed after you learn Replacable Parts. Demo has far greater problems with WW, can not only riot, but completely overthrow your government into anarchy.
If in Republic you have to leave some interior cities unguarded, doesn't that make for losing those cities? Especially what if you have a right of passage aggreement? Or what if you have alot of really agressive neighbers that don't like you? Is the switch still worth it?
Guard your border cities only and do NOT make ROPs with the AI if you're concerned that they may backstab you.
Is Monarchy better if I keep getting dragged into wars and have a pretty big army?
You can do a lot of war in Republic, and the WW count begins over again when you are at war with a
different civ. It's only a problem if you have a long war with
one civ or are losing units and/or cities. Monarchy is for playing Always War, never ever having peace.
I also managed to build the military acadamy and even without it I managed to pop 3 great leaders wich I used one to rush the project, one to build and army, and another I am saving.
Do you mean the Heroic Epic, which is the Small Wonder that helps you get more promotions and leaders. The Military Academy builds an actual army without a leader.
Are you aware than, when you save a leader, you cannot get another one until he is used up?
Again, I ask if I should trade for some techs, or should I stick with gpt? What's better in the long run? (This relates to the Democracy question, whether I should aim for Democracy or not).
Again, it depends for trading. As for Demo, I think Republic is much better and you can get it earlier without researching the additional techs and suffering through another period of anarchy.
