Photo-realistic graphics and shit, you know it's going to happen.
Source engine was flawless and had the most revolutionary physics system in the first person shooter since Trespasser.
Assuming HL3 is going to be on valves new engine, we can expect this coming generation to continue the current golden age for another 5-6 years.
Left4Dead 3, Counter Strike 2014, Gary's Mod 2.
I can't even handle it.