Environment and character work was generally great in 4, but just look at that Phantom 'explodes' in the very first mission... It's remarkable how weak some of the presentation in the game was. While 4 did have some talented people working on the franchise still, it was obvious by then that 343 no longer cared and QA was absent. Also way way too much lens flare
Halo 4 only looks good if the only thing you care about is how quickly your GPU can fry an egg. The art style is ugly, none of the levels are lit in a way that makes any sense, and the new designs look dumb.
There is nothing good about Halo 4, including the graphics.
The video details how all of Halo 2's assets were made with stencil shadows in mind after the bungie devs saw it in Doom 3. However, the OG Xbox ended up not having the processing power to do those critical, deep shadows, so they returned to the flat lighting of the first Halo, which resulted in a much less stylized game. The video creator shows how the game was meant to be experienced by showing all of the different character models in one of the few places in the game that retained a small section of dynamic shadows, which really drives his point home of how much better it would've looked overall.
This is a really interesting video. My first question would be why this issue wasn't caught early by the devs. The Id Tech 4 engine at the time was considered absolutely cutting edge stuff, and (as the video identifies) even it had to be constrained to interior environments. Halo 2 was using an iteration off of Halo:CE's engine, so unlike Doom the engine wasn't specifically built to do those shadow tricks. Who thought that they could rework an existing engine to do shadows like this, get it to work better than Id Tech 4 at doing outdoor spaces, and then get it optimized enough that not high end computers but X-Boxes could run it? And do all of that on top of actually just making the game itself inside of a market driven timeline?
Laid out like that, it looks like a crazy idea. I wonder if the art style was developer or management pushed, and who allowed it to get far enough that models were made with it in mind.
Apparently the games that did use that technique, like idtech games and splinter cell, generally all had small environments that were within the limitations of the hardware, where as halo 2 had massive environments that stressed it too far with the lighting active.