Grenades are pretty OP, so the nerfing was inevitable. I personally eschew grenades, seeing them as a glorified and legalised Ctrl+Alt+F4... They make the game too easy. Oh sure, they disappear, but you could just fill up your inventory with them, guaranteeing a victory by smashing the army to pieces through the action riding back and forth from the battle chest and back into the fray. No fun. And they appear to drop morale more than non-lethal musket-shots or edged weapons somehow - I always see clumps of routers after each grenade hit.