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.
I think The Chronicles of Riddick on Xbox was running on idTech doing all them effects on the OG xbox. It looked fantastic.
https://www.youtube.com/watch?v=Xu5BH4j0K1A
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.
That’s great, though it doesn’t really address the questions. I suspect only higher up people in the Halo 2 development could answer them.