Class 1 medical for IR, even if attached to a PPL?
That would kill it for a lot of people. So far to my knowledge you needed an audiogram and some additional requirements for the Class 2, but to get a class 1 medical would be the show stopper and also again make the IR impossible to achieve for a lot of folks.
There's no requirement for a Class 1 being proposed. IO-540 is simply pointing out that the existing audiogram requirement for an IR is not being relaxed.