I doubt folks waiting on the HPA have really thought this through. A quick reading shows that there is no provision for removing the onerous requirements for transfer of suppressors already on the registry so those of us that complied with the pre HPA laws regarding the cans classified as firearms are sort of stuck. The removal of suppressors from the NFA restricted firearms classifications does NOTHING to preclude State legislators (known to be fat greedy money grubbing douche bags) from enacting laws to regulate/restrict/tax them.
I think there is a provision to nullify state requirements - which is as it should be.
And I'm one that believes HPA can pass, but I'm a dreamer.