-A single NFS session uses only one uplink, but when there are multiple NFS sessions, wouldn't load based teaming allow the next session to choose the path with the most available bandwidth?
LBT will balance vmkernel ports, not sessions. If you're using one subnet, they will all choose one vmkernel port.
http://wahlnetwork.com/2012/04/23/nfs-on-vsphere-technical-deep-dive-on-same-subnet-storage-traffic/
So all the configuration and tuning I do on VMware doesn't give the hypervisor visibility into how much traffic is going to end up getting crammed on one physical Xsigo port.
Indeed. 