Blue is the name given to the rival of the Pokémon games and to a major character in the Pokémon Special Manga. The name widely used outside of Japan, due to a mix up between game releases. So, how does this name change fit the character?
Blue is often associated with depth and stability. It symbolizes loyalty, wisdom, confidence, and intelligence. This shade of blue best represents the Blue of the manga. He is powerful and always plans out his attacks before he makes his move. During the battle against Koga, Blue played dead in order to get an opening and claim victory. He always thinks before he acts and always keeps his cool. The Blue of the games can be rash and overconfident but his loyalty to himself keeps this color from fitting his personality in the classic sense.
Light Blue is associated with health, healing, tranquility, understanding, and softness. Neither Blue fits with this shade; both are offensive players who would fight, far before they ever considered healing or backing down.
Dark Blue represents knowledge, power, integrity, and seriousness. The shade also fits the Blue of the manga; he has a wide array of knowledge on Pokémon because of his grandfather and his childhood of fighting and training Pokémon. Blue also has power; he is the second best trainer in the series. Blue is always serious and is almost never seen cracking a smile.
Overall, the name change is only representative of the Blue of the manga. The two Blues are almost polar opposites and the characteristics are only slightly representative of the game Blue's personality.