Serious question: for a transatlantic network, would it ever make sense to do something along the lines of buoy + helium balloons + laser or microwave? Or in a similar vain, would it make sense to attach microwave 'towers' to shipping vessels?
I could see something like that work really well for the HFT world, where some clever hacks could make use of an unstable, but extremely low latency connections.
For inter-landmass traffic, my gut feel is bandwidth is the bigger concern.
The latencies we see now (as noted in TFA) are not that far from theoretical limits. I'd suggest responsiveness is best solved further up the stack -- and it's what most organisations have done / are doing.
Basically you don't want to run chatty protocols over high RTT networks, and people are slowing getting this ... but many orgs are stuck with HTTP, MAPI/MoH, SMB/CIFS consuming most of their WAN bandwidth.
I doubt that would be lower latency. Even forgetting the physics and curvature issues, you'll end up with many more hops which is going slow it down due to processing and retransmission delays.
I could see something like that work really well for the HFT world, where some clever hacks could make use of an unstable, but extremely low latency connections.