If you disable the nfs_export_all_rw boolean, then take note of the following:
For content to be readable by NFS, it should have the public_content_t or nfs_t SELinux context. For content to be both readable and writable, it should have the public_content_rw_t or nfs_t context. If the public_content_rw_t context is used, the nfsd_anon_write Boolean must be enabled to allow writes. Additional NFS-related SELinux information can be found in the nfsd_selinux(8)