I've been playing this game off and on since DL was first released. Still enjoying it when I have time to play it.
I've always felt some of the races behave strangely in TA versus DL and DA. For example, I've seen the Thalans colonize like crazy with 1 colonist on many of their planets. Or, some races just sit there and do nothing. At first, as an experiment I, did a mod that reworked a couple of the tech trees to make them more DA like. It had a dramatic effect on the performance of the races. For example, the Iconians were often one of the races that would sit there and do nothing. With a new tree, they moved out like gangbusters. So, I went ahead and redid all the tech trees. The races are much more competetive with the new trees and behave similar (better) to the way they do in DA. It makes for a different TA game to say the least.
If you would like to check it out, following is a link. This is a TA only mod and works best on larger maps and higher difficulties. There's actually a ton of stuff that's been changed aside from the tech trees. Look at the INFO.txt and README.txt files in the zip archive for more information.