Very unlikely, because it assumes there is only one question, which we both know. Generally questions are manifold, making 'a good question' more likely. In actual usage, dobre pytanie is closer to 'good question' and 'a good question' to 'to dobre pytanie', purely on amount of emphasis.
You seem to be mistifying us. Sometimes answers without "jest" aren't accepted, even though they would mean the same. Now "this good question" isn't accepted, because there is a full stop. "To dobre pytanie" means "this/that good question", as well as "this is a good question", so I do not understand why you have a problem with accepting either.