As planning ahead is a major part of managing a War properly, I would be against the idea of ending rounds early. It might be OK if it was done only after a 12/12 vote in favor of by current Generals.
Nah it't more like when all matches are played there no reason to begin next round later. And if it would be posted earlier it should still be up for the same amount of time as before + the time it being posted earlier. So it wouldn't change much but you see the brackets earlier.
This alleviates my concerns. For example, I was foreseeing a scenario where a General has to be out of town for the ending of a phase and beginning of the next phase (but not all of either phase) within a Round. General leaves, that phase ends early, and then the next phase now ends before their return. That would not be right. However, what you propose with
only moving up the end and subsequent phase start without adjust forward the next phase
end makes a lot of sense.