We should use in regard to something or with regard to something. Here regard is an uncountable noun meaning attention to something.
However we use as regards something because here regards is a verb meaning to look at something.
The answer to the presenting question is:
is ungrammatical because you won't wind up owning the door by virtue of my opening it.
Ordinary bitransitive verbs of transfer (tell, throw, bring, hand, pass, send, etc.), where the direct object (the trajector, semantically) is transferred from the subject (the source) to the indirect object (the goal), normally are subject to the Dative Alternation:
- I'll tell/throw/bring/hand/pass/send the answer to him.
- I'll tell/throw/bring/hand/pass/send him the answer.
Besides these, however, there's also a Benefactive construction, which uses for instead of to, and identifies someone for whose benefit something is done. This can be added to any sentence, 3-place bitransitive, 2-place transitive, or 1-place intransitive. Here we discuss only the transitives:
- I'll open the door for you. (Note -- you don't wind up with the door)
- I'll dig a clam for you. (Note -- you do wind up with the clam)
- I'll fix the car for you. (Note -- you don't wind up with the car)
- I'll fix a meal for you. (Note -- you do wind up with the meal)
In precisely those situations where the Benefactive object of for ends up possessing the direct object, the sentences can undergo Dative; in those cases where they don't, they can't.
- *I'll open you the door.
- I'll dig you a clam.
- *I'll fix you the car.
- I'll fix you a meal.
The last two sentences show that this extension of Dative to Benefactive is not governed by the verb used (fix in both cases), but by the intended meaning of the clause, including idioms, presuppositions, and metaphors.
Best Answer
"What is wrong with XYZ?" is valid regardless of whether XYZ is one thing or many, and whether the questioner expects an answer detailing one fault or many.
If the questioner wanted to explicitly indicate that he expects an answer listing multiple faults, he'd have to say something like "What things are wrong with XYZ?".
"What are wrong with XYZ?" is never grammatically valid. Nor is it a common mistake — I don't recall seeing it before now, and Google Books records only 14 instances of "what are wrong with", compared to millions of "what is wrong with".
As regards exactly why the non-standard usage is unacceptable, rather than just uncommon, what in this construction is a non-count pronoun. Non-count nouns require the singular verb form.
Edit: Kudos to JLG for highlighting the importance of the word wrong in this construction. The interrogative pronoun what attaches to wrong — a non-count abstract noun which transfers its non-count status to what. That doesn't happen with, for example, "What are those things?".