Now here's a thoughtful consideration of what makes good military history by someone worthy of consideration--and I read it differently with you having posed the question!
"The Most Important Principles For The Conduct Of War To Complete My Course Of Instruction Of His Royal Highness The Crown Prince," by Carl von Clausewitz, 1812, republished by the Stackpole Co., 1960, as "The Principles of War;" pp.67-8.
"These difficulties ["The natural timidity of humans, which sees only one side to everything, makes this first impression incline toward fear and exaggerated caution."], therefore, demand confidence and firmness of conviction. That is why the study of military history is so important, for it makes us see things as they are and as they function. The principles which we can learn from theoretical instruction are only suited to facilitate this study and to call our attention to the most important elements in the history of war." ...
"In addition, only the study of military history is capable of giving those who have no experience of their own a clear impression of what I have just called the friction of the whole machine."
And then he gets to the root of the "historical" question, both through negative criticism of what had constituted much historical writing in his day and clues about what would make the study more effective. I found in this some interesting echoes of this current thread.
"Of course, we must not be satisfied with its main conclusions, and still less with the reasoning of historians, but we must penetrate as deeply as possible into the details. For the aim of the historians rarely is to present the absolute truth. Usually they wish to embellish the deeds of their army or to demonstrate the concordance of events with their imaginary rules. They invent history instead of writing it. We need not study much history for the purpose we propose ["Your Royal Highness, therefore, must become acquainted with these principles in order to check them against the history of war, to see whether they are in agreement with it and to discover where they are corrected or even contradicted by the course of events."]. The detailed knowledge of a few individual engagements is more useful than the general knowledge of a great many campaigns. It is therefore more useful to read detailed accounts and diaries than regular works of history."
I suppose I have come, independently, to agree that those sweeping campaign analyses only take one so far. Great introductions to subject matter, but they usually leave those they have made interested hungry for deeper appreciation of cause and effect, decision and outcome. Hence, while one may be apprecaitive of another one-volume study of Napoleon's wars, or of the Peninsular conflict, once hooked, the market (having pandered heavily to generalist surveys) offers a very limited range of deeper examinations--there is little follow-on available. By the very nature of a generalist survey, it is difficult to know the extent to which its author has embellished, created odd emphasis, ignored crucial themes, or largely invented in the work, for it inevitably lacks much in the way of detail. One sees the shadows on Platos cave-wall, but yearns for a glimpse of the fire...at least its coals.
There are lots and lots of the generalist survey-histories--and there is a place for them, certainly. But most of the really enduring history (assuming attributes like, well-written and well-researched!), I suspect, is that which examines and offers more "detailed knowledge" rather than simply "general knowledge of a great many campaigns." (I think that may be one of the attractive aspects of staff-histories, their commitment to detailed study.) "Detail," of course, being of the sort that illuminates and corroborates, rather than overwhelms and bores.
Cheers - Howie