Cardassians and Organians were in ENT? When? I missed both references. Can someone tell me when both happened?
I believe that it certainly could have worked to have the Cardassians appear because, as far as I remember, it's never been established onscreen when the first contact between the Federation and the Cardassian Union took place. However, they got a lot of exposure in DSN, and what would've been the compelling reason to have them on ENT?
Also, I personally believe the Federation didn't have contact with the Cardassians till the 24th century, around the time Picard was captain of the Stargazer. I also happen to think Betazed didn't become part of the Federation till the 24th century, but that's another topic.
It worked to have the Andorians and, to a lesser extent, the Tellarites appear because we only had glimpses of them in all the other series and movies. So for all intents and purposes, they were largely unknown to the ST audience, making them ripe for exploration.
Red Ranger