He was basically as good that day as anyone has ever been...at anything.
If you'd have asked most of us on May 7, 1998 how many career strikeouts Kerry Wood was going to have 10 years later, we'd have given you a number higher than 1,337. But since that time, he's torn, shredded, or strained basically all the connective tissue in his throwing arm.
That's not all on Dusty Baker, although Wood's workload in 2003 was obscene. He threw 120 or more pitches 13 times that year, and maxed out at 141. But it's also worth noting that Wood also once threw 175 pitches in a high school doubleheader. He had some mileage when he arrived in Chicago.
Anyway, today he's an iffy relief pitcher (three blown saves, 4.50 ERA) and an interesting buy-low candidate (14 Ks and 3 BB, 0.81 WHIP). Wood used to be just a little bit better than that.