Understand however from a network access perspective its not really an issue of Standard vs Distributed though with Distributed you have better control over certain aspects.
In regards to the cluster-to-cluster communication, as long as you provide redundancy for the communications and the heartbeat is able to get through, there are no issues. In our case we are running 2 X 10 Gbps for the VM traffic so going to the extra effort of creating a separate Network (VLAN) to pump this traffic across seemed unnecessary. Your mileage may vary but its worked fine for us for quite a while.
In regards to Always On - your thinking is correct. In a cluster you have a shared volume and if this gets corrupted/deleted/whatever then your data is offline. With Always On you have a second copy of the data online. Doesn't prevent issues within the database but does at a disk level.
Kind regards.