I´m also a fan of the Civilization series and have only recently started playing GalCiv II.
The tech-trading is unfortunately quite a bit worse in GalCiv than in CIV for a few obvious reason.
a) The tech-trading screen is much less informative in GalCiv than in CIV
(for instance, you do not see how many recearh-points a certain tech is worth, nor can you while still trading, navigate other menues for more information about wheater a trade is a good deal or not like you can do in CIV IV for instance)

There is much, much, more tech in Galciv II to keep track of (or at least several versions of the same tech) while much less information is available so tech trading can easily become a micromanagement-hell.
c) A.I values techs quite strangely at times.
d) there is no "what will you give me for this"-button in GalCiv II. Every time you are suggesting a trade, tehere is a lot of micromanagemet to be done.
I played a few games with tech-trading enabled and quickly firgured out that the game is much more fun with tech-trading disabled.
It´s a pity though that disabling tech-trading really disables all tech-options.
It would be nice if you still could demand tech as tribute for instance. Or gift tech to a weak race as a way to help.
In addition the diplo-screen dialouge is incorrect for some reces when they make demands with tech-trading disabled.
They may for instance claim that I am to poor to pay them tribute so I have to give them some tech instead. Then, since tech-trading is disabled they still only demand gold and in many case very small amounts of it. (I even had one case where the Yor Collective demanded 0 gold in tribute order to let me live)