I agree with the general sentiment here:
Simultaneous turns, tech trading OFF
I think 48 real time hours is a good amount of time for the diplomacy and democracy aspects.
I think tech trading should absolutely be OFF. With tt on, a civ can just get dragged along to tech parity. So, the #1 group will always be on the cutting edge. On the other hand, with tt off, it is much more difficult to always have the 'leading edge', because each team must choose which part of the tech tree to do first.
For instance, a team could decide to go for CS for Bureaucracy. With tt on, that team could expect to get gifted Music or Literature and Drama or something comparable. So, the team will be able to compete for the great library, temple of artemis, sistine chapel, and all of those wonders. On the other hand, with tt off, the team is sacrificing its chances at those wonders for the benefits of bureaucracy. I think no tech trading would make this game far more enjoyable. Diplomacy would concern far more than the formation of a tech alliance. Say no to massive tech conglomerates and yes to more interesting gameplay.