>But beyond that, I'd say the biggest problem with it is that there are just so many exceptions that knowing the rules of grammar is nowhere near enough to speak it correctly.

My experience was that English and Urdu are much worse grammarwise. In the latter, it's not so much that there are exceptions to rules - it's that the rules are the exception. Most of the language doesn't follow grammatical rules. It's not as bad in English, but the problem exists. When I used to help people learn English, I could see how frustrated they would get whenever they'd ask a question and they'd be told "yeah, this is just how it is".

IIRC, most of formal Arabic is covered by first level grammar rules. The thing I found interesting about it is that the exceptions themselves have rules. So it wasn't a case of "just memorize that this is an exception" that you'd have for other languages. It was "Here's the exception to that bigger rule, and you know if a word/phrase should follow the exception based on these rules". I think the challenge you speak of is that sometimes even the exceptions had exceptions.

I'm not a native speaker, so I may be wrong. Overall I found it the most structured language amongst all of these. It's not simple, but it's not haphazard.

(Speaking only of formal Arabic).