I agree with this idea. It should be required to have at least some experience in all of MCGamer's platforms, and your post count is what reflects your time spent on the forums. Getting involved in the forums is not only a way to show you have experience using the forums, but also gets your name out there for the players you'll be moderating for.
Your second point is also important. Having people know you before you get moderator. Personally, I find it a lot more comfortable contacting a staff member I at least know a little bit about than someone I've never seen before. It's just that piece of mind that makes the staff team just that much more approachable.
It's not cause I'm new, it's just extremely hard to please everyone around here..
It's not extremely hard, it's near impossible. As long as your putting thought behind your posts you'll at least be giving a good impression about yourself. You won't be pleasing everyone, but you're post will at least stand out from the one-sentence posts people tend to make.