A History SE site could potentially cover everything that has happened before now -- from history of programming languages, to history of basket-weaving, to history of synthetic fibers, etc. Each of these would require very technical expertise in each of these fields to provide a decent answer. They might best be answered in the specific SE site for those topics -- ie programmers.SE, basket-weaving.SE, fashion(?).SE.
Consider that SE sites only deal in the facts world, and almost every fact is tied to a well document event in the past. So with enough leeway History.SE could cover every topic.
Where do we draw the line? Do we cover anything that happened in the past?
Would you consider very technical questions "too localized" or "off topic"? For example:
- What programming languages heavily influenced C?
- How did quantum theory impact astrophysics in the 20th century?
- Did Freud's approaches to psychotherapy influence Jung?
This gets hairy fast, certainly military strategy/tactics could be considered their own field. But Military History is also a strong thriving area of research with very strong overlap with strategy/tactics. For example would the following questions be on topic? Or would they be better addressed by
- Why did Robert E. Lee fail to win at Gettysburg?
- What tactics did Wellington implement to defeat Napoleon?
It would seem natural for these questions to fall into a History SE site, but also a hypothetical site for expert tacticians or strategists.
tl;dr: To sum up, how do you differentiate a question that is too technical vs one that is appropriate for History? Where do we draw the line between what's acceptable and what's too technical to answer well here?