Regarding runaway thermal events, there is unfortunately no amount of electronic control nor digital sophistication on the outside that can stop the sudden internal short circuits that are the hallmark of these lithium battery failures and fires. The battery structure itself requires a redesign. For now, better manufacturing QC is the focus.
And then again; why would he do this? Is there some lobby that has said there is a huge cost increase if Lion batteries can not be bulk shipped by pax a/c? Changes in these kind of policies are often due to money. Or is this being too simplistic?
The official line is to ensure a steady supply of Li batteries to "remote areas" for "medical devices" etc which seems a bit far fetched in the overall scheme of things considering if a passenger aircraft with room for substantial belly cargo can get there, so could a freighter (or a truck). Perhaps Trump's choice of ignoring the ICAO is simply contrarian, his logic being "if Obama wanted it, it must have been bad" - reality be damned.