You mean a battery of 6 cannons may rout an entire corps ? Yes, if the corps has no artillery.
It is difficult to imagine what impact had artillery on infantry, but for sure, it was called in french « le Brutal » (the Brutal) for a clear reason : it really hurts.
As almost everything in napoleonic wars, cohesion is a determinant factor of victory - in cavalry and infantry fights - and cannonballs used to sweep the rabble from Earth with a terrifying efficiency. A unit with « holes » is overexposed to charges, and fear spreads in the ranks.
If the infantry/cavalry unit is very close to artillery, it uses grapeshot and then it is the debacle...
Therefore, I don't think artillery is too powerful, it is historical : great batteries were quite invincible (in Wagram : about 100 cannons commanded by Drouot).
« God is on the side with the best artillery » said Napoléon.