Sorry, but it is pretty easy to say "if I had hearing impaired children"... If you really have a child with this problem your role of parent is to take decisions for him. Parents MUST decide for their children. And you have to decide for what you think is the best option. Making this means considering carefully all the pros and cons, evaluating the risks and being strong in going over the worries, because every parent would kill himself instead of exposing his child to any risk.
What's the sense of the role if you simply wait they grow up? You avoid responsibilities and the risk of doing something wrong,letting your child to take the risk.
There are so many decisions every mother and father take for their children, think about cultural habit, religion, education, experiences offered. What should they do? Do noting, close the children in a room waiting for them to grow up and when they are old enough ask them if they want to be catholic, protestant or whatever, if they want to go to a technical, scientific, or professional school, if they prefer to be free, or to follow rigid rules while they live in the family? And if any medical decision has to be taken, easy: if you can, just wait until they can understand and let them to decide...
How can you think like that?!?!
The parents have to decide for their children, until they can decide for themselves.
Parents who decide to implant their child simply play their role. They give their child the possibility to develop spoken language more easily (hopefully) and give the child the possibility to choose between spoken language and sign language at the end. In many cases if you decide to not decide, you are deciding anyway. The decision is making your child signing only.
That's OK, parents could decide the want their children to be signing only, there is nothing wrong with that. But it has to be taken in mind that deciding to wait until they can decide for themselves is the opposite of being a parent.
And CBJ, waiting till your son is 6 or 7 and let him decide is a nonsense. A child cannot be really able to make such an important decision at that age, c'mon!