You should expect around 66% read IOPS from a boot storm, login and the first time applications are launched. After that, normally expect 66% write IOPS, so something looks unusual. Check the WIndows OS to see what processes are creating the Disk IO, but as a first test increase the RAM to 2GB, I suspect your OS is paging a lot increasing the Disk IO.
Regards, profiles, if you are just using a local profile, this will mostly just read certain components. If you intriduce roaming profiles, the SAN will need to read the CIFS share, and copy the entire contents to the Virtual disk, so will acutually increase the IOPS required, and slow down login.
As said above, separate your replicas out, and if possible on the array set the cache to 100% read.