What's considered "acceptable English" almost always says more about the prescriptivists than it does about the language itself. Preposition stranding is perfectly acceptable (and actually preferred) by native speakers, and I don't believe that "who" really has case in English anymore. I often see native speakers attempting to use "whom," but invariably distinguishing "whom" from "who" not in that "whom" has object case but that "whom" is a relativizer:
in reply to Re^4: The Germanic language form
in thread The Germanic language form
I like to visit my grandmother whom always gives me delicious cookies. (also see this)
The notion that modern English should adhere to Latin grammar rules is actually quite ridiculous when you think about it: modern English is separated from Latin by a thousand years, and isn't even descended from Latin (English is Germanic). This notion is more attributable to the Western infatuation with everything Classical rather than any property of English itself.
This isn't to say, of course, that standards shouldn't be adopted to try to make English as intelligible as possible to non-native speakers in appropriate circumstances, but these standards should be understood as outside impositions towards maximally helpful language use rather than as characterizations of good language use.
I apologize if this is way too off-topic.