For most things retouching, Adobe Photoshop sets the pace and has been the industry standard for decades. However, as alternative software improves and innovates, there are some features that Photoshop doesn't have that would improve it.
I have been using Adobe Photoshop for nearly 20 years, which can't be true, but sadly is. I picked up the software in my early teens when I wanted to make websites in Dreamweaver and I got a little hooked. Photoshop seemed unthinkably complex and deep to the point of being tantamount to impossible to master. Now, I look back and I see that it was comparatively simple compared to today's iteration
A big part of why Photoshop has been in the industry standard for so long is because it is the industry standard. That is, to maintain its position at the top of the pile it had to keep improving and innovating to quench the ever-growing thirst of its users. However, somewhere in the last decade or so, we have seen the rise of many alternative programs similar to Photoshop. Some try to do more than Photoshop will ever try to do by becoming a "one-stop shop" for post-production and some try to do what Photoshop does, but offer it to their users at a much lower price. Whatever the case, these lesser-known applications have had to innovate just to get a sliver of the market share, which has lead to occasions like the premise of this video: a Photoshop alternative has powerful tools that Photoshop itself does not.
What tools would you like to see added to Photoshop? I must say, since watching the video, it surprises me that, as Abbey Esparza says, all tools in Photoshop don't have live previews as they do in Affinity.