I agree with not putting in age limited benefits in the contract, for example you don’t get the retirement notification bonus if you were less than 54 at age of signing (which makes no sense to me). While I don’t know that ensuring that retiree health care costs aren’t exorbitant may not encourage people to retire early, allowing the company to massively raise costs at their whim certainly discourages people from doing so. And making sure that retiree benefits don’t suck is not an age limited benefit, it’s a benefit that is available to everyone if they choose to utilize it.
I, for one, would like to retire by 60, but if medical costs are ridiculously expensive, I will have to rethink my strategy and possibly delay retirement.