Tech trading off makes it easier i think? It did at monarch at least. I'm pretty sure it will be easier then. AI's trade between themselves so cheap, it's a pretty big disadvantage for them to have tech trading off.
up to noble you have a bonus on research and production on the AIs
from prince up, they have a bonus.
At emperor, the bonus is serious enough to make it very hard to keep up without a good trading strategy. I'm not saying it's impossible. But it's hard.
+ no tech trading makes bribing AIs one vs the other very hard too
.I'm pretty sure I can win monarch without tech trading.
I can also win emperor without tech trading easily, but it will be cultural
. No tech trading makes the overall tech rate a lot slower, making a halt on research at liberalism not too much of a risk
. Other than this, I can't see how to leverage diplomacy efficiently, and since emperor is the first "diplomacy or die" level, I fear there may not be a lot of good options.
. One thing I've learned about war is - better soon than later. Build an army and conquer AS SOON AS POSSIBLE. Even if you have to slow down your research and buildings. This means whip/draft a lot if you need to. The AI's are also less likely to declare war on you when your army is large... out of anything I find a large army prevents the AI from attacking moreso than being 'pleased'.