Rory & Co.,
I am going to sneak in and toss a bomb. I think that appropriate footnoting (coupled with bibliography) both sustains the integrity of the work and the marks out a path for further exploration by the reader.
The footnotes can help the reader discern which works in the bibliography may be of particular interest to the reader; they reveal directly the sources the author relied upon for data.
While helping a friend lay out a magazine on Napoleonic history, I was floored to discover just how poorly even established histories could be with getting facts straight, chronologically ordered, and logically related. Frankly, it could be very frustrating to wonder what could be trusted without direct reference to contemporary evidence! (I think particularly of the series of articles we gathered on Marengo, alas never published, and how clear it was that the story could be written a variety of ways depending on what sources were used, ignored, or unnoticed!) Survey histories are especially prone to error, but error easily and unwittingly made for the very reason that it doesn't (can't) review the nuts and bolts that underpin the sweeping statements any survey must make. I think those surveys are even harder to write well than the in-depth study!
Underneath the footnote issue is, for me, the real core concern: not length or style, per se, but the transparency of intellectual debt, an evidentiary trail, and factual or suppositional corroboration that footnotes can represent. Frankly, there is great history, pretty good history, and a hefty dose of rubbish that panders rather than illuminates.
Cheers (and, plop!, back into my fox hole!) - Howie