My current RDM configuration will allow me to simultaneously write to this LUN since the LUN writes command will be sent directly to the storage which I believe the storage file system (We are using NetApp) supports that.
Yes on the SCSI block storage layer this is not a problem, but this is irrelevant. It's about the filesystem your Guest OS uses to access the storage device.
For example, VMware's VMFS is a clustered filesystem that was specifically built to support simultaneous write access of many hosts to the same SCSI block storage device. NTFS however does not support something like this and needs Microsoft's CSV extension or third party software that makes plain Windows NTFS cluster-aware.
You would face the same issue with two physical windows hosts accessing the same LUN.
In order for me to view the file-level changes real-time, I have to use the CIFS protocol on these Windows Guest OS.
CIFS/SMB is a network based file access protocol, it's completely oblivious to the underlying filesystem or storage device/protocol being used.