As a developer, champions are a response in character to pressure the player. Bungie is a company that seeks to punish the player for mistakes. That is the reason they respawn you like thirty feet back when you make a mistake in a jumping puzzle. Make more mistakes (and die) and they will respawn you even further back. Denying a player enough ammo, impeding health regen, slowing movements, these are all “punishments” that pressure the player. This design philosophy really started with the earliest doom maps. I don’t care for it, I think it’s shame based(or bound), you take away, restrict, impede, not my cup of tea (it is effective design wise and easier to implement). The other way to pressure a player is to design ads that are just as fast, can jump as high, or deal as much damage as a player. Designing encounters where a player is ambushed, has multiple lines of incoming fire, must move under fire to cover, and have ads never spawning in the same place again is less cost effective. With ai this may change, a smarter ad will allays be harder to kill. Spawn points that change according to player position will also increase difficulty. Restricting a player to increase difficulty while more cost effective, will never be as fun or rewarding for the player as designing difficulty.