I did watch through the video, and find it astounding that you can get any work done while simultaneously & continuously talking & reading & responding to that text thing on the left.
If you had 5% of the experience with KiCad compared to Altium this would have been 2 minutes of work.
To Try to keep short I will only comment on one thing, because I found it too painfull to watch (as you also predicted @12:53 in the video).
You spend almost 10 minutes (From 49:25 to 58:09) talking about a feature KiCad presumedly does not have, and then at 58:09 you accidentally do exactly what you want and even more, but you do not recognize it because you are talking too much and distracted by commenting to the others.
Another reason you did not recognize it is because the design rules are set much smaller than what they were originally routed on. So KiCad does not only straighten 3 traces with one mouse swoop, adjusts the trace spacing to the current design rules. It has also placed those traces off grit. Design rules take precedence over grit settings, as you are explaining @51:30. I appreaciate you want to give constructive feedback to the KiCad team, but it will not be necassary for this feature.
I even managed to capture a screenshot of the straightened & off grid routed traces.
This works so well that I only use a grid for placing components and holes and such, and ignore the grid for routing traces. Trace widhts should be defined by DRC rules, not by some grid. You say Altium users keep changing the Grid all the time. I just ignore it (or set to < 1mils).
Note 1: If you do not want the traces hugged so closely you should edit the design rules for those traces, and not use the grid.
Note 2: Traces can also be locked.