Just watched the video. Here are my thoughts-

Overall, it's a pretty fair assessment of the changes between Dark Souls and Dark Souls II, though he does make a few comparisons between aspects of both games that weren't meant to be related, such as the Sif fight and Royal Rat Authority fight.

I was happy to hear him note the distinction between lore and plot. Dark Souls' convoluted, rich lore provided the game with a very absorbing setting, and contributed to the game's astonishing atmosphere. However, the plot of the game was minimal, straight-forward and lent itself to the game's pacing. In the end, the player would be paying much more attention to the lore as they experienced the world left in ruin from what happened before the game takes place.

Dark Souls II shifted this storytelling weight onto the plot, and while they undoubtedly made the plot more complex than Dark Souls', they also made it more convoluted. At times, it was difficult to follow, and I believe this is because the developers intended it. They really harped on the "without really knowing why" chord throughout the game. Ultimately, it felt as though Dark Souls II's progression was being driven by the player character, rather than the player, as it was in Dark Souls.

There were a few points in his video that the developers themselves addressed in SotFS: the overavailability of healing items and the lack of early game weapon diversity. In the original version of Dark Souls II, it was remarkably easy to oversupply yourself with healing items and quickly upgrade your Estus Flask. In SotFS, they did a much better job of spreading out the Estus upgrade items. You can still have a fully upgraded Estus Flask halfway through Drangleic Castle, but the upgrade items aren't nearly as frontloaded as they were in the original game. They also took time to relocate the Dull Ember so we could obtain it much earlier in the game, which allowed for more early game build diversity but unlocking McDuff's weapons and infusions.

Quite a few more things come to mind, but this post is already running long. The guy was harsh on the game, but we have to bear in mind he prefaced his discussion by stating that he still did enjoy Dark Souls II. I'm in the same boat: while I thought Dark Souls was a much better game overall, I ended up playing and enjoying Dark Souls II much more thoroughly.