As cool and promising as this idea was, the end result of so many lightsabers in this particular scene at once is not an improvement over the original film. And of course he who shall not be named’s edit was just awful alone for its terrible voiceovers.
Don’t forget obvious editing, like Ackbar being rotoscoped into some shots, like having him replace the old lady who introduces the Resistance crew to Holdo just so he can provide info about a spy, filling in the plot hole of why Holdo never told Poe the plan. There’s also footage that is taken from EA’s Battlefront II.