Well, I won't bother talking about his exeptional fielding (8 gold gloves) since you only want to know why he's a great hitter.
Look at his stats. He's over 200 hits and .300 average every season. He broke the record for hits in a season with 262, a record that stood for 84 years. He also holds that same record for the Japanese leagues. He has a career .331 average. He'll be surpassing 2,000 hits this season. He has amazing speed and won a SB title. He's the only player in baseball history to have over 200 hits in every season. There are 2 players that have more than Ichiro's 8 200 hit seasons, Cobb and Rose. The difference is Ichiro is 8 for 8, Cobb has 9 in 24 seasons and Rose has 10 in 24 seasons. Ichiro has led the league in hits for 3 straight seasons, and this season he will try to become the first in the history of baseball to lead in 4 straight. Is that enough for you?