not really. I see those as good trade-offs as you get to choose whether you want damage or kite more at earlier stages of the game.
I should point out that one of the main reason kai is so strong, is because of the rageblade, deaths dance, nashor build which allows her to get all her evolutions at 3 items. The standard adc build on the other hand pigeon holes you into going pd and berskers, and even then you have to be lvl 14 to get the evolution on her e. If you were to go for rfc or statik, you'd be required to build another attack speed item to get your e evolution, which then denies you ga, a lifesteal item, or a pen item depending on the situation.
Eventually, rageblade will be nerfed and/or the way kaisa abuses the interaction between that, nashors, and deathdance. If you were allowed the 8 percent attack speed the standard build gives, Kai'sa could get by with the standard ad build and wouldn't be so dependent on rb, dd, and nash, of course this is only assuming they are nerfed bc right now it would be too much of a buff with the current iteration of rageblade