I don't buy it. Here's an example of the opposite: Maori is analytic (morphologically "simple"), while German is agglutinative. Of course, for this to work you'd need to be a racist asshole and assume that Germans are smarter than the indigenous people(s) of New Zealand. Let's. :Spin:
Joking aside, I think it should be pretty obvious that language differences have nothing to do with development gaps between cultures. What a language lacks in one area it compensates for in another, so everything evens out *.
* An exception is "domain loss", but that is the result of culture affecting language rather than the opposite.
I'll elaborate on the point I was making.
In English, the sentence "where are you going" contains the word "where," which asks about a place, "are" which is a conjugation of the verb "to be" that is either second person singular and plural, first person plural, or third person plural, and "you," which I don't need to explain, and "going" which is a form of "go" that contains an ending that illustrates an action in progress. There is so much specificity in the communication of the concepts that one does not need to think about the situation or anything to understand the sentence.
In Korean, that sentence is two words: eodi kayo? (I don't know the different Romanizations, but phonetically, it's like "uh-dee kah-yo," though the k almost sounds like a g). eodi means "where" and "ka" means go (no tense specified), and "yo" is put at the end of the verb to make the sentence polite. To know that that sentence means "where are you going" you have to think about the situation. If you do that with everything whenever you speak, I can see how your thoughts can end up more in-depth habitually.
I can read for scholarly purposes all the language I need to know (Ancient Greek, Latin, German and French), though I might try to improve my Italian since plenty of classical scholarship's in that language too. Don't have much interest in any others though Classical Persian or even Classical Arabic could be useful.
Classical Persian would be a nice challenge for you, but you'd pick it up very quickly with your knowledge of Latin, Greek, and English. For example, the word for wolf is varka, which is a cognate of "warg," and past is "pasā." I can't remember any more words off the top of my head, but your biggest trouble might be the writing. They use an adopted form of cuneiform that is syllablary, and Persian has almost as many sounds as Sanskrit.