Is there any evidence to support the claim that a Voice to Parliament could stop or slow down progress?
The Voice only has the power to make "representations." How these are handled is a matter for the executive and Parliament. Nothing in the proposed amendment, either directly or indirectly, says that the government has to accept them.
In the proposed change to the constitution, the Parliament would also have a substantial amount of authority to manage the relationship between the Voice and government institutions. If a lawsuit were filed, it could be dealt with quickly by a court. There is no chance that government will come to a standstill.
If it is working properly, the Voice will have an effect on public decision-making, but the aim is to improve decisions and enhance "progress," not to impede it.