What I mean is, if you took the chief military powers in history, at the height of their power and from their respective eras (e.g. British Empire in it's imperial century) and compared them to the military strength of their rivals, could you determine the strongest nation? If so, what would it be?
No, I would call this rivet counting.
What you ignore by doing this is how and why militaries work, how politics and diplomacy work, and more importantly, the random acts that often drive war.
A case example would be the Army of Italy in 1796. It was a poorly supplied, poorly trained conscript army with good officers but tired men. The Austrians & Piedmontese were far more numerous, well supplied, and battle hardened. It would not be until Napoleon came forward and delivered a new system of warfare that success was had, and even then luck worked in the favor of Napoleon.
Looking at the best of the best with only statistics ignores the human element that decides things.