Fine posting, gentleman.
I wonder who might have formed the assault force, then? Do we have an exhaustive list of the members of the White Council? If not, other "names" like Glorfindel might have been involved. Thranduil or his people are likely participants, as is Celeborn, both of whom would later clean up Mirkwood. His failure to ever mention it probably means that Aragorn was not there, though his links to Gandalf, Lothlorien, and Rivendell makes this surprising. Perhaps other Rangers were there?
Sadly, it is probably too much to imagine a company of sturdy Hobbit archers amongst the vanguard.
What makes the most sense to me is that Saruman played "the" major role in the assault of Dol Guldur. Hence Gandalf's statement about the importance of Saruman's "devices". In my mind, I could see Saruman defying the intent of the Valar and using some level of might/magic directly against Sauron as he clearly had started to turn. My take is that Saruman had already been crossing the black and white lines (with shades of grey) laid out to him and the other wizards by the Valar (and maybe similar to Saruman of many colors whose robes appeared to be white upon first glance???). This is, of course, all conjecture, but its conjecture from a part of The Hobbit and The Lord of the Rings that wasnt clearly defined in the book.
So heres what Ill go out on a limb and wonder about since this part of the history isnt defined. Ever think about the Palantir and the role it may have played in the assault of Dol Guldur? It makes sense that Saruman already had it and used it for quite some time. Were sure he had already started down the wrong path. It makes sense that he may have thought he was reading the purposes of Sauron. AND, it makes sense that Sauron knew he was being watched. Might that not have been the reason Sauron fled Dol Guldur and returned to Mordor? If Saruman had unwittingly given Sauron access to the plans of the White Council (and I think it clear that, at that point, Saruman wasnt under the thumb of Sauron), it would have made the assault of Dol Guldur seem like a victory, but, in reality, a clever feint by Sauron. It was only when Saruman was unmasked and didnt have access to the plans of The Council of Elrond (and in a more extreme measure when Aragorn ripped away control of the Palantir) that Sauron didnt know what was coming and acted rashly. Ultimately, this led to his defeat.
I think Gandalfs words to Pippin after the Palantir was recovered in The Two Towers fits with all of the above. He said something to the effect of How far back his treason goes, who knows? A spider in a steel trap. A hawk in the eagles claw. Saruman wasnt always evil, but when he forsook the tasks put before him, his demise was inevitable.
The battle at Dol Guldur, if detailed similarly to the above, could have, in my opinion, fit the spirit of the book and offered an interesting interpretation of it.
In other words, bring in more about the role of the Palantir and Saruman and less about the Lake Town and their petty hagglings. Bard played a small part in the book, but it was a noble and important one. We didnt need to have a birds eye view of his toilet.
Ill take my interpretation over PJs, but, who knows, maybe mine wouldnt have sold.