The important part is the feedback of the RPers, because PS is supposedly geared towards them and thus they must make sure that the development progresses in the intended way. Without feedback, development will have a much harder time going on as originally intended.
Therefore, it is almost mandatory to post ideas and feedback so the devs can have a reference on how their efforts impact the game and it\'s ability to fulfill it\'s stated goal of being RP encouraging.
Yes, it might be that simply letting things \"develop themselves\" would reach a similar outcome eventually. However, it would often stray off the intended path and thus waste a lot of effort and time.
By providing feedback, we can help to keep PS on track and thereby protect it from getting slowed down in development by straying off the path and having to undo things that took time to do but proved to not work towards PS\'s goal.
Also, by providing feedback the devs can, if they wish, more easily measure how much a certain feature would likely impact the game.
In summary: to prevent development from slowing down due to wasted effort.