Agreed that testing on an ERP is no easy feat.
But I support the idea of a public RC. Advertised efficiently, it would be a good way to get users into the pool.
After all an RC is supposed to be stable, it's what we want to release. It has already passed the beta stages and we consider this should be the final product so it shouldn't have any major defect.
Ideally consecutive betas and RCs should be published at a fixed rate, eg. once a week so there is enough time between each to make some work.
Also, when done correctly, the final release _is_ the last RC.