I will admit that "volo iudex esse" is correct alongside "volo me esse iudicem" after having found examples to corroborate this,
but still all with copulative verbs. Keep in mind, however, that the number of examples I've found of the type "iudicem" dwarves by far the number I've found of "iudex" (only 1 or 2). It seems to me that an acc + esse is the preferred construction.
and that such is not ungrammatical, even if a Graecism, seems fair to assume, since Rome's greatest poets may be said to have been able to write correct Latin
This is a terrible assumption. Poetry bends rules in any language, for example, I flipped to a random poem in English, John Wilmot's "A Satyr against Reason and Mankind," and we have at l. 33: "His wisdom did his happiness destroy." Now, if we were to apply your logic to this sentence, we should assume that this is perfectly natural English and normal people would go about saying this. But, obviously, this isn't the case. It is highly stilted English that you would never find outside of highly literary poetry. Now, this situation is exacerbated by the situation in the ancient Roman world even more so because of its society's situation. Authors wrote for less than 5% of the population, all of whom learned and spoke Greek and read Greek literature from the time that they were about 5. The authors knew that they could get away with non-normal Latin based on Greek grammar because of this peculiar situation they lived in. And whenever you hear "in poetry," it should be a sign that you're dealing with something that is highly abnormal and potentially difficult to understand even for native speakers. The very fact that we don't find this construction in prose, where there are no restrictions on how an author can express himself, but only in poetry, where stilted grammar needs to be employed to fit meters, is a dead giveaway of this as well (especially in Latin since Greek meters didn't necessarily fit Latin all that well all the time).
somewhat exotic with 'sperare' but totally normal with "velle/etc.",
You'd better check your dictionary, both OLD and Lewis & Short disagree with you. And you've yet to demonstrate that you can just line up complimentary infinitives in complex sentences in Latin, which I find highly skeptical. Your only examples are simple sentences with copulative verbs as the verb directly subordinate to the verb of wishing, which is not very convincing. So, please, quote something with a transitive subordinate verb and with another verb subordinate to it that is not poetry.
Most men are rather stupid, and most of those who are not stupid are, consequently, rather vain.
-A.E. Housman