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.