lol it's not a generational leap. not even close. doesnt even look as good as horizon or god of war.
BUT the fact that they have completely reveamped the level design to be an open world and add all kinds of animals,.... so many animals... is a great new direction for the franchise and what i have been begging MS to do for years now. Do a full reboot of Gears now.
I think one needs to not only understand the context of why he says "generational leap", but also one needs to understand all the tech he's talking about in the video. You can't just "LOOK" at a game and understand everything that is going on. Lighting, materials, scene density, particles, etc...has to be taken into account. A game may have better "art direction" or "look" better to you based on some form of visual preference, but it doesn't mean that the tech and what is happening in each scene/frame is on par with or pulling off the same tech engine wise.
So if he is only referencing any leap in comparison to the Halo series, then I'm sure he's correct. Even if he's comparing it to other games currently on the market, the tech side and the things the engine is pulling off can also be correct as a "leap" or something needing higher-end hardware to be rendered at that level.
A lot of people base their thoughts on simply looking/glancing at a scene...but don't take the time to understand everything that is going on in it visually.