Separating iSCSI traffic is definitely a good thing. However, having only two 1Gbps NICs for Management, vMotion, and VM traffic may introduce a bottleneck in production, and/or during backup (unless you're backing up directly from SAN).
You could use a single vSwitch (for redundancy reasons) for these 3 traffic types with Teaming & Failover configured in a way where Management, and VM traffic use vmnic0 (active), and vmnic 1(standby), and vMotion has the configuration the other way around, i.e. vmnic1 (active), and vmnic0 (standby). This configuration would avoid possible issues when vMotion runs, as it can easily saturate an uplink, but it would leave only a single port for production traffic.
If I were you, I'd probably try to get an additional 2, or 4-port network adapter for this setup.
Moderator: Moved to vSphere vNetwork