Urgot Ultimate Change

I was thinking about our very loved and often picked Urgot and pondered a change to his ultimate. Urgots ultimate doesnt do too much good as an adc that tries to stay at the edge of all team fights. Urgot is seen as a corrosive, missile firing monster so I think his ultimate should fit his style. My proposal is to make Urgots ultimate fire an AOE missile that significantly reduces armor and MR. The game needs another adc that shreds tanks and this change would add just that.