I know some people don't like the ground ones at all. In general, I feel more competent at ground combat and even then the ground ones feel a bit harder due to heavier reliance on gimmicks. KA is by far my favorite ground map and the big gimmick there really feels like it's "whether you complete the optional" in time.
Infected feels a bit bloated, The optional feels significantly harder. But it is very PUG completable.
The Cure... ugh. I don't see how most PuGs will ever complete this one. A standard completion here is much harder than completing either KA or Infected with the optional objectives. If there was one STF that needed to be nuked and replaced on normal mode, this would be it.
My suggestion, similar to how the forcefields make KA and Infected easier, would be to only make the current forcefield device and the previous one attackable by Borg in normal mode. That means once you get the third one going, the first one no longer needs to be defended. Once you get the fourth one going, the first two no longer need to be defended. On normal mode, I think the focus should just be on defending two at a time.