KuGB also spanks the KuEx, due to the ability to remain indefinately in the KuEx's weakzones, and when the KuEx forces a straight line chase, the KuGB is far, far harder to hit than the KuEx.
Where the KuEx shines is against lone bombers (particularly heavy ones), and fighters. Obviously against increasing numbers of either, it is at a severe disadvantage. But one person shouldn't really be able to take down five other people based solely on the technology at their disposal, in my opinion, unless flying a battleship.
Just about anything can kill a transport, so.. eh. Balancing based on that seems a little daft.
In short, I have no complaints about the KuEx in its current state, or availability.