In NS1 you could only choose one upgrade from each type of chamber!
Now in NS2 you have onos/fade/lerk with BOTH carapace and regen.
There's no tradeoff, you can both take more dmg AND heal up quick.
It's like a super-life-form!
If onos chose cara, he'd have to run back to hive to heal up, or slowly heal by crag/gorge.
If onos chose regen, he'd be much less unstoppable!
Tradeoffs! Design doc!
Also, the first level of upgrades is the full one; in NS1 there were 3 levels of upgrades, meaning gorges had to drop 3 (or more) of the same chamber to max the upgrade.
THIS is why aliens can deny so much ground control, cos they can just retreat slightly, hide, heal up, and then push again! In NS1 you often had to go back to hive for healing.
THIS is also why gorges are so much less needed - they are built in into the aliens already.
It doesn't help that crag tech is the one and only viable sarter for aliens currently...
(THIS is why all games end with marines being pushed back to spawn in mid-game when aliens get 2 hives. Again, second hive is make-or-break.)
Suggestion: GO BACK TO NS1!