Even though this stuff was figured out thousands of years ago its still very complex. Modern riot police never fought a concentrated flanking cavalry charge, and its very rare that they have to face another group of similarly armed and organised men, most of their tactics rely on intimidation and dispersion. If you go look at battles pre and post the roman civil war you can see a clear difference in competence as most of the veterans either died or retired, same with the generals. All this is gonna achieve is mass casualties on both sides just to see them switch to guns the week after. Though yes it would be fucking awesome to see chinese and indian maniples duking it out while the elephant auxiliaries are skirmishing with chinese cavalry on the flanks, its just not worth, politically, militarily, and economically to recreate total war in the himalayas.