The medical needs to be the same for everybody. Tighten up the requirements on the basis of age is discriminatory. Tighten up the medical and you might be surprised how many YOUNG people can't pass.
Besides, you don't even need a 1st class to fly Part 135. That is a Company requirement, not an FAA requirement. I can do all my Part 91 and Part 135 flying with a 2nd class medical.