I also find kids that are allowed to have soothers put more things in their mouths because it becomes a habit of always having something in their mouth.
I agree, IME this is what I have found as well. My daughter only had a soother at night and I took it away at 6mths. She still mouths things but not nearly as much as the little ones with soothers.
"If we all could see the world through the eyes of a child, we would see the magic in everything!" - Chee Vai Tang
I have actually found the opposite in that the children that needed something in their mouth all the time could be satisfied with a soother and then they left the toys alone.