No, the GTI didn't talk a lot, but when they did, it did its job.
If you're looking for the general character of GTI pilot you were going up against, I'd look no further than the Ransom-voiced pilots in Mission 3 and the EMP mission. If you didn't get the idea that you're going up against obedient, well-trained pilots in possession of technology more advanced than yours, then I think you missed the whole point.
Additionally, the GTI doesn't talk a lot ingame for a good reason. An easy way to build intelligence on an enemy force and gain an enormous advantage is by simply knowing which channels enemy forces communicate on. The easiest way to give this information out is to simply speak to your opponent. Once your opponent knows you can operate on that channel, it doesn't take long for them to figure out what others you operate on. Once that's all understood, everything from fighter launches, strategic maneuvers, and deployments are all available for your enemy to listen to.
Now, maybe on Hercs and other fighters used by both GTI and GTA, this is less of an issue...GTA already knows what those craft are capable of. But having Lokis and Zeus bombers give away their comms strips away the GTI's advantage.