If there was a weapon of choice in in the ancient India, besides of elephants it would have been bow and arrow. Cheap, readily available ranged weapon kept the enemy far and distant for as long as possible. Disorder and possible casualties by barrages of arrows might have been tempting to anyone that thought of warfare from perspective of efficiency instead of personal valor.
Could say that massed archery would even form an macabre artistic display. It may have been that the personal valor and display of power was reserved only those of superior social standing, where the mass of troops deployed only as a backdrop.
Levied infantry of indian armies were armed in two-fold way. Bamboo long bow for range, and then perhaps a sword for shock combat (there is no certainty, and it does appear that Indian infantry preferred to keep the enemy at bow’s range instead of shock combat). By no doubt it was suitable for Indian kingdoms and empires where manpower pool was not of major concern.
It is probably debatable wether Indian armies, such as Maurya Empire were powerful simply because they were genuinely good and well organized and disciplined, or because they were able to replenish losses constantly. Nevertheless, combined arms tactics were present and apparently successfully implemented.
Force multipliers that other armies may have possessed – such as training of troops, discipline etc. would have been overcome by quantity in prolonged conflict.
However professional, and well trained military may be, it is bound to sustain irreplaceable losses during prolonged conflict against one that may constantly fill ranks with new recruits or levies.