It's appearently that. I play the terrans, with really good diplomatic abilities and the Diplomatic Translator but now I have to give a lot more stuff for the really cheap techs. Mabe they are just smarter now that they don't think they need your tech. Like the AI now is really reluctant to give you their top weapon tech. As soon they researched a better weapon they will be much more willing to give it to you. So now they can kind of like judge the importance of the techs and what they don't want you to have.

I don't know...

It's DEFINITELY more challenging -- but with some diplo wonders/goods -- you can still make good deals, especially with the lower diplo AIs. I have found that the AI holds onto the colonization techs like grim death - but they'll still deal (almost) everything else. I think it's a matter of knowing what you can get the AI will all but give you: research, industrial, defensive, and econ techs -- which they absolutely won't: colonization, planetary invasion, initial/final weapon type techs -- and which are pricey: mid level weapons in a group.

I find now that on Obscene/Suicidal - I can no longer run the table as the most advanced race -- BUT I can still stay relatively even.

I might be wrong - but it seems the AI doesn't trade with other AIs as much anymore either... I use this to my advantage by being the 'trade broker' -- i.e., all trades go through me. With the 'dead period' between trades - it does mean trades need to be better timed... no more trading the first time we meet- I wait until I can trade with 3-4-5-etc races in a single turn.

Th eonly reason I hate disabling tech trading is because I can't give the AI Alliances so I can end the game diplomatically when it's pretty much foregone that I could win if I spent the time on it.