I like having Kimahri because he is so versatile early in the game. If you want another black mage, you can have one. If you want another powerhouse, you can sure have that too. This time around, I chose a more stength based Kimarhi (first time I played I let him learn Lulu's grid). Although I don't think he necessary, it wasn't a mistake putting him in the game. I love having options !

It depends on how you developed him. I just finished his grid then started him on Tidus' and then integrated him into Wakka's and finally aurons so he basically had the best of the 3 worlds.

I somewhat agree, I didn't really care for kimarhi too much when playing, but the fact that you can shape him into the type of battle combatant which suites whatever styles you want was pretty good. I always made him follow Rikku's grid and made him a thief.

I did that at first but to me that made him even more useless because his attacks were weak. Maybe it's just me but when i first saw kimarhi i thought he'd be like a power house type character.

He was ok. I never really used him much till late game but I feel he adds more depth to the story line and creates Yuna's and others personalities in more detail.