I think that it is a great idea! Suggest that you or someone submit a new issue with title ”Option to build Z-Wave Repeater firmware for ZWA-2” as a feature request to Nabu Casa’s silabs-firmware-builder on GitHub:
I believe that building such a firmware image built there would be the first step to make that happen as it would allow people experiment with less risk of bricking it using an official firmware image.
Note that the readme has not been updated to reflect the fact that their Silicon Labs firmware builder there is in fact also used to build Z-Wave Controller (i.e. Z-Wave NCP) firmware for the ZWA-2 adapter, however it does, so in theory it only needs a new manifest file with correct configuration to build a Z-Wave Reapter firmware for ZWA-2:
But such a Z-Wave Repeater configuration for the ZWA2 adapter will need to be much more advanced since it needs to be able to be used as a stand-alone device and also need way to reverse the process by flashing the original Z-Wave NCP firmware in an easy way.