I know the tech trees are all race customized but I found that effect to be largely homogenized later game due to extensive trading between races.
I turned off tech trading for this reason, but the end result is just as painful in the other direction - no tech trading removes a pretty vital part of the game.
My preferred fix is that if you do not have the tech on your tech tree, you should not be able to trade for it. This will eliminate unique tech acquisition, as well as all instances of imbalanced tech design (ie: Torians getting Discovery Spheres, making their research ability go from the worst, to the ridiculously over-the-top best).
At any rate, after TOTA goes 'live', I might make a tech tree mod that increases the costs of things exponentially. Through the course of the game, I've noticed that with a few exceptions, the length of time it takes to get new techs never really goes up at all. In fact, according to the techtree.xml, most weapon techs, like phasors, sometimes get CHEAPER (meaning faster to research) the more advanced they are. This makes no sense to me, and I tire of games where the enemy is constantly 'leapfrogging' technology as a result. I like 'very slow' tech because I like to *USE* it before it's instantly obsolete.
As for trading itself, I tire of the one-sided AI favoritism. I'd like to be able to play as an arms dealer, pitting sides against each other and selling them ships, but the AI simply refuses to pay anything more than 25% wholesale price for your ships, while for YOU to buy a crappy little scout, will cost trillions of credits.