You should also check your switch ports config. I've seen issues in the past where switch ports are set to 1000/full and ESXi hosts are set to auto and there is some flapping around - both should be set to auto.
If this is a production environment tread very carefully making changes to your storage network.
Can you check the properties of the iscsi initiator and have a look at the 'network configuration' tab - is it showing any warnings under port group policy, or is it compliant?
Looking at your config you should configure it like this providing you are happy the connectivity is set up correct:
ISCSI-1 vmnic2 active, vmnic3 unused
ISCSI-2 vmnic3 active, vmnic2 unused
Check out this short whitepaper on iscsi multipathing as it may help you in troubleshooting further