NO its not possible. And you will never know how bad it is untill u work for them, and am trying to pay for an apartment, and cover ur wife and all other matters of life while working for them.
It is not possible to change wal mart. They are an all controling entity that can not be stopped. The only way to slow them is a union. And if u union a walmart, they instantly shut down that walmart. it doesnt matter how much money they will lose they will kill the store. So u want to try and change them? Unionize as many of ur store u can. then change might come but never untill then. sorry to burst ur bubble. This will never work.