Its easy peesy to do.
Please give a step by step guide how to implement the walking/running sound if it is so "easy peesy" to do for you. I am waiting.
More background sounds/noises, why not, but footsteps sounds? I am not sure it would bring more life to the game, I can imagine how it would sound if there were multiple things moving (horrible), also it would be wierd if there were same sounds for metal, sand and walkway floors. And I am not sure that with current engine those problems I mentioned could be solved without awfully much work.