I would've loved to see the Cata storyline incorporated in HW2 though.
I'm glad that didn't happen. Cata would have been miles better if it had built on the Ghost Ship from HW1's Sea of Lost Souls instead of introducing a silly organic version of the Borg.
Oh, and let's not forget that a kiith of miners has loads of fancy tech that no one else has. And the Bentusi became hateful towards anyone who wasn't part of their buddy club. Gameplay-wise, supply limit encouraged just building one thing and nothing else, whereas HW1 and 2 had limits on each class type, encouraging diversification. Energy cannons completely ****ed over the capship-fighter dynamic. HW2, despite its failings, was much more faithful to HW1's gameplay, theme, and atmosphere than Cata ever was. Which is why I say Cata is decent as a standalone.
I could go on, but I've had this conversation so much over the years I've gotten tired of it. Have a search through the Homeworld series forums at Relicnews if you want to see.
As an aside, I gave up modding HW2 for exactly the same reason Matth did.