Everything Taichi does is for Chihaya, which I would normally applaud, except for the fact that Taichi is petty and cheap. The only reason he tries to avoid being himself (cheap and petty) is to appeal to Chihaya, which in itself is petty and cheap. He needs a better raison d'etre to be a better character.
Arata is quite underdeveloped as a character, but even then, he is much more likable.
Also, Chihaya and Arata are hardworking. They practically devote themselves to Karta at this point. There really is no "genius without effort" character in this show, maybe excluding the current king until his inevitable development flashback.