Exadata RMAN vs. Non-Exadata RMAN - any differences? Can you please let me know the differences, if any,  in the architecture of the non-Exadata RMAN vs. that of the Exadata-RMAN from an SBT plugin perspective?

Have you observed from your vast experiences when non-Exadata RMAN and Exadata RMAN existed as separate architectures?

Do you anticipate any behavioral change from a RMAN perspective going forward from now between the standard and Exadata infrastructures ?
There are no architecture differences in RMAN itself.  The difference is in the speed of the backups if written to the Exadata on-board storage.  So the advantages that Exadata brings in terms of hardware would also translate to advantages in backup speed and MTR (mean time to recovery).  But none of those advantages are the result of changes to RMAN.