routable or non-routable iSCSI VLAN??
We route our iSCSI for two reasons:
1. SAN-SAN replication to remote site
2. Management - no dedicated management interface in our arrays without sacrificing one of the iSCSI data transfer port
We do put an ACL on the iSCSI VLAN to restrict traffic to just the needed management ports, and the iSCSI port between the local & remote arrays. That also prevents initiators in servers or wherever from accidentally making a connection over a routed path vs. a dedicated NIC directly on the iSCSI VLAN.
I'd say if you have no replication need, and if your system has dedicated management interfaces, then don't route iSCSI.