To create new races simply by adding new dialogue misses the point of creating new races. To suggest that the Thalan leader is the penultimate woman in the game means that not only you have missed the point but have regrettably aimed much too low.
There's more to races than snappy dialogue. They also have to do things that are (stereo)typical to their culture.
Thanks to Star Trek, we have the Kilingons, the kissing cousins to the Drengin. They are incredibly warlike, which is handy for a wargame, which is why this type of civ always seems to show up in sci-fi games. Then you have the Ferengi, the traders or Space Republicans if you will. Then you have various minor Trek races that seem to embody various human cultures, i.e. (IN MY OPINION ONLY) Bajorans (and Zeons) roughly equal the Jewish culture, Cardassians roughly equal Arab culture, Ekosians = Nazis, etc.
But apart from the Drengin, very few of the GalCiv races play up their sterotypical traits other than to talk. The Iconians, for instancearen't terribly wise in most of my games, usually, they're just Drengin-fodder. The Thalans don't do anything insecty (or feminine), in fact, usually they are friendly in my games.
The Torians do have one trait that sets them apart from everyone else: they reproduce like mad. Thing is, they never talk about it at all. You'd never guess by talking with one just how randy they really are. My gay brother-in-law talks more about his bedroom conquests than any Torian (not that I want to hear about that), but at least our family knows he's getting some. My point here is, if you're dong "it" a lot, you tend to talk about "it" a lot, too.
In my examples above, there's plenty of room for adding scripted civ events:
+The clumsy guys can turn the fate of battle just by being clumsy, i.e. Jar-Jar Binks
+The see-thru guys are hard to see
+The brain-in-a-jar guys always have equipment that is extensions of the brain in its jar (Sort of like "Mars Attacks!")
+The gamblers will offer bets as to the outcojme of various space battles
+The Illusionists create phantom ships and armies
+The Space Geeks clog up the Internet with their forum commentary (guilty as charges)
and so on.
Unfortunately, this means more than just adding some dialogue and pictures that are cute as a bag of kittens (apologies to David Mamet here). It means some kind of hard-core game programming stuff, the kind of thing that Stardock is paying their pixel monkeys to do, and, unfortunately, also the kind of thing that's beyond even my admittedly oversized bounds of creativity, at least not without getting paid.