The Show wasn't out at the time but even now you can compare the gameplay of the two. WSB2K3 did not have online play though, but certain things like arm strength and for example Scott Rolen's trademark dive, set, and throw wwas portrayed the exact same way on WSB2K3. Even the way the ball was spread out with different hits was very realistic.
I love The Show but if 2K9 has the old school gameplay and the graphics of 2K8 then The Show is in for some competition. Me, I will buy both.