Please, please add the ability to monitor hardware RAID health from within 1) the host console and 2) XenCenter. Just some way to view/alert on the relevant RAID statuses - i.e. degraded, rebuilding, etc.
Without this ability, it's like working blind - you have to physically reboot the HOST and launch the RAID configuration utility to determine whether the RAID is healthy.
At the very least, integrating smartmontools into the default Xenserver install would be nice.