The design confuses me a bit. Considering it's now a single unit, they could have redesigned it to be more comfortable to hold and play with, but instead it mostly adopts the design of the original Switch (for recognizability, I guess). At least it has a D-Pad. Would have been really weird to not use one here.
Maybe FailSandwich is referring to a fault that can occur after using Joy-Cons a lot, where their sticks can actually start to "drift", sometimes moving into random directions? I've had this problem on my first Joy-Con pair, but Nintendo repaired it for me for free. I also kinda doubt they can do a lot about this, because I expect the culprit of this to simply be the small size of the Joy-Cons. Small technology just tends to be prone to break.