Exactly. He likely makes adjustments here and there and may learn over time, not to swing at pitches he doesn't hit very well. He's only 26 and will probably improve without making any changes, due to experience and refining his own approach.
Plus, it's not as simple as just saying lay off ____ type of pitch. Pitch recognition is done in such a small fraction of time, it might mess a hitter up by asking him to start thinking while doing what comes naturally- without thinking.
Like from that book I mentioned "Out of Your Mind," that speaks to the idea that once you start thinking about something during play, you lose that edge.