I don't see a problem with the new baby swing. All it does is help with the baby's moods. It doesn't do anything with aging and that's the main thing in this challenge.
Exactly. Also, it's not like child trait selection is affected by nooboo or toddler moods - it is all based on learning all the toddler skills.
Where the swing could offer an advantage is in reducing the amount of time we have to spend on child care - thus freeing the time up to continue working on skills, careers, and the like. It's not an issue once you have a house full of adults to share the childcare responsibilities but it might make a difference in the first generation.
I've played with it a bit in another game file I have going and honestly it seems to be a wash. You don't have to spend as much time taking care of the nooboo, but left to their own devices Sims seem to turn it on high and make the baby nauseous. Then you have to calm the nooboo down, so it may not really be much of a time saver.