Can't comment directly re Hertz. But there are definately changes going on with car hire companies and third parties, eg, carjet.
I have several trips booked, both short break weekends (3 days) and longer trips. I am having to look very carefully at the car hire vouchers for the fuel policy - all of them used to allow full/full on a 3 day short break, but now this varies depending on car hire company and even which third party you booked through. Likewise, the second driver, with some third party eg carjet you always got a free second driver no matter which company you were placed with, whereas now you have to check this carefully as this can differ depending on company/third party.
Finally re the excess, last year we bought an annual policy for £80 I think it was. This covered myself OR my husband AND any named drivers on the car hire agreement. (Alternative was £50 to cover ONE main person plus any named drivers, if we always went together we could have saved some money!) Haven't had to claim on it, but the peace of mind of having it is very re-assuring and would have cost a fortune to have an additional insurance everytime. We've not had to show it to any of the car hire companies, when they ask us if we want the extra insurance we just say no thanks we have our own. They then invariably tell us if we have a problem we have to pay the excess directly to them then claim from our policy later, which we are happy to accept.
Just remembered something about Hertz, some friends who are using our place in the summer have booked with Hertz, he told my husband it was only third party insurance - worth checking.