I have questions, questions....
Not doubting there is logic in your points Suzzane O, but Darcy is such a strange man that I'm not sure that even Jane Austen knew exactly what to tell us of him. Yes, he visited at Hunsford Parsonage after just arriving at Rosings, but almost five months had passed since he had last had contact with Lizzy and his alternative to visiting was to spend time with Lady Catherine and Anne, a not very scintillating prospect. He also must have been aware that the Bennets would be less than happy with Bingley's absence and his association with Lizzy would inevitably lead to questions he might rather not answer? Did Darcy even know that Lizzy was at Rosings? He may have known if Lady C had mentioned such in her communications by letter to him, but she appeared surprised, even annoyed on finding Lizzy knew him? Darcy was not the sort to indulge in servants chatter, so ...? How did he know that, in five months Lizzie may not now have become engaged? Was his early visit to the Parsonage because Mr Collins had told him that he had visitors when he lay across a puddle in the lane so their horses could ride over him? (joke) Was it feasible that after the same five month absence he had dashed there to propose to Lizzie....at his Aunt's empire? Their last meeting had hardly been a great social success when Lizzie tongue-lashed him about Wickham. Had he actually spent any time at all thinking about Lizzy's fine eyes?. He dashed in and declared passionate love and how he could no longer contain it, then reverted to type by telling Lizzy how fortunate she was that someone of his standing should step down off his golden cloud to honour her with his offer.
And so on and so forth......one very odd fellow is Mr Darcy....