I actually think the new Light system is much more complicated than the old system. And just as punitive. Allow me to explain.
Why it's more complicated. Before you only had to know your level, the enemies level & your weapon. Now you need to know:
1. Your Character's Level
2. Your Character's Light Level
3. Your Weapon's Attack Value
4. The Enemy's Level (Nightfall & Normal raid are 42)
5. The Enemy's Light Level.
They added two more variables by making Light a variable rather than just a score.
And remember how fighting Crota or Skolas one level down resulted in a massive 33% damage penalty? Well, if you're like me and keep getting 300 raid drops, what does that mean for when I try Hard raid? Someone took the time to figure out the damage penalties from being under-light:
This also means that players who go into the upcoming King's Fall hard mode at 300 light (the lowest recommended) will have a massive 42.5% damage penalty at the 320 sections
More here. Even being 10 light down facing a Hard Oryx is a 28.5% penalty.
Welcome to Year 2.