To add a few of my own experiences ...
[a] Often when I have a chance to use some German, I find that it doesn't work because the German person goes into English and stays there !
[b] One of the biggest problem stems from the three genders.
The minute you get one of them wrong, you're labelled as an idiot.
The % of your brain that gets used up with remembering German genders must be huge.
[c] I'm glad she mentioned those separable verbs, and how we have them in English.
I've never seen it mentioned in any language books, as a sort of comparison.
Sometimes it makes you feel like chucking it all in. ( in-chucking).
And at other times, you feel all messed up (up-messed).
And eventually you resort to throwing all your grammar books out ! ( out-throwing).
And half an hour later you sheepishly bring them back in. ( in-bringing).
[d] As she points out, German is a "rare"language.
Unless you're in Germany and related countries, you're not going to get to use much of it.
Or hear much of it.
[e] And here in the UK schools are dropping German in droves, because they need good grades, and German is tough, so out it goes.
[f] So fewer and fewer people know any of it.
[g] And there's fewer and fewer German teachers.... you see where this is going !
Das ist ein Teufelskreis !