Everything else. The structure and policies of the company would need to be entirely rebuilt from the ground up in order to make Kspace a decent workplace. Every day is utter chaos, with next to no time given to plan lessons and prepare materials. You are expected to teach a variety of after school classes everyday, which you may or may not be given time to prepare for. There is a real emphasis on marketing and media, with less attention given to the actual content of a lesson. Moreover, the owners expect you to stay late and provide absolutely no additional compensation for your time. Any and all insurance and pensions pay to the Japanese government comes out of your paycheck. Simply put, unless you are a qualified teacher, the compensation given doesn't even come close to covering the cost of work done.
Worst of all, there is a culture of blatant sexism at Kspace. The owner, a woman herself, very clearly favors her male employees. Just about every woman I know who has worked at this company has been bullied or otherwise demeaned by the owner. The number of times I witnessed a colleague crying due to the owner's bullying is, frankly, alarming. If you are a man, you will probably be treated fine during your time here. If you are a woman, I strongly advise against even applying at Kspace.