http://pubs.vmware.com/vsphere-4-esxi-installable-vcenter/index.jsp?topic=/com.vmware.vsphere.esxi_server_config.doc_41/esx_server_config/raw_device_mapping/c_benefits_of_raw_device_mapping.html says
An RDM provides a number of benefits, but it should not be used in every situation. In general, virtual disk files are preferable to RDMs for manageability. However, when you need raw devices, you must use the RDM.
So as your VMWare team say, virtual disk files are preferable to RDMs, but also as this link says when you need raw devices, you must use the RDM and a phyiscal server can't use a virtual disk file, hence the need for RDM.
The only other solutions I can see would be to use NAS, so present a network share which can be moved between the 2 servers (or share the data from one of the nodes to the other) or use VVR so you have 2 copies of the data that you replicate between your nodes.
VVR is host-base replication over IP so can replicate from VMDK on virtual server to phyical disk on physical server (see https://www-secure.symantec.com/connect/forums/sfhadr-vvr-running-physical-and-virtual-server)
Mike