German has a difficult grammar (was a real pain when learning German as a kid) but at least when reading German you know how to pronounce it, English pronunciation like German gender must be learn by heart :)
I am not sure whether this can be objectively measured. All kids learn (at least) one language the natural way. I have the strong feeling that related languages will always be easier for them.
I speak English as a foreign language. I don't think articles in English are a challenge. It's the USA, but not the France. I can feel the cold or a cold and know the difference. I don't know many rules, it's mostly like I would use them in my mother tongue.
I have many colleagues, whose mother tongue does not know articles at all. If they write a page of text, there are often a dozen of mistakes related to articles to correct.
But it's not that I would just be smarter. I have spoken another foreign language daily for over 25 years. I speak fluently and can make myself fully understood. Still I make quite some mistakes all the time.
"Weg" <- how do you pronounce this?
"Geh weg" (go away) "Der Weg ist da drüben!" (the path is over there)
You missed "Gehweg" (sidewalk) though. :^)
But German pronunciation is 80% simple and regular at least whereas English is more like 80% complicated and irregular.
I don't know what you're trying convey in your examples though, because all the example have consistent pronunciation. Inconsistence pronunciation often because it is borrowed words from French (das Experiment (Ex-pe-ri-mo'n?)) or English (das Schedule, informal vocab.)