How about "Be kind/nice, do X"? It's grammatical - of course, it's a weird thing to say, but the entire point was that the literal translations are weird and/or pushy. "would you be so kind as to" is indirect in virtue of being a question and not containing an imperative; of course, it's the correct translation, but it's really a very different construction.

Ah, yes, I see your point.

I think I agree with what you're saying sufficiently that anything further would be nitpicking. I do think it would be interesting to study this in more detail, although (not having any formal training in linguistics) I am unsure how linguists approach quantifying e.g. politeness, etc.

By the way, do you live in Russian or another Russian-speaking country? Because I've seen a study that showed that heritage speakers of Russian (i.e. speakers who live in a different linguistic community but learned the language from a parent) adopt more English-like politeness strategies. The reference is here.

I live in the United States, having been born in Russia and learned Russian in the usual way. (Interesting citation, though.)