I see similiar IOPS in my environment, with a similiar VM's, up to 4200 IOPS during a refresh of 30 linked clones.
I'm scrambling to figure out a solution other than dumping money into SSD's.
To get the most accurate data on disk usage, I recommend using esxtop from the esxi host.
Great info in there, just wish there was a way to specifically see replica IO load.
-D