1. Console sales outnumber PC sales, or at least they did a few years ago. Meaning no mods for most players.
2. I didn't specify because the discussion was on the number of torches placed, but the problem is not just the visual piece. It's the requirement that the player understand an invisible mechanic. Magnum torches don't fix the underlying issue.
3. Turning off mobs is not a reasonable solution.
I'm not talking about using the current system to prevent spawning, I'm talking about making a better spawning system. There are a ton of ways the game could handle spawning rules and making an area safe:
* Could track what blocks were naturally generated vs. placed by hand, and spawn enemies away from player made structures.
* Could refuse to spawn mobs around any blocks that don't spawn naturally.
* Could track visited areas in a separate file per chunk, creating a sort of lightmap for what the player can see, and only spawn enemies in unvisited areas.
* Could create more detailed rules about where mobs spawn, such as having zombies rise out of the dirt or endermen falling from the sky.
* Could decouple the lighting system from the radius-based safety. For example: enchanted items that work sort of like a magnum torch. Or (a closed loop of) crafted fences/walls could prevent spawning. (3D presents issues of course)
* Could use a game-of-life style system to track migrations/populations of friendly and hostile mobs on a per-chunk basis.
* Could mix and match from the above.
And that's just from less than five minutes of brainstorming.