Definitely not Half-Life 3, though.
This has been answered throughout. The short version though is, XenForo 2's goal is to reach feature parity along with some new framework that makes it much easier for developers in the future.This debate is going for well almost 1.8 yrs. but there is no clarity as to What would truly define xF 2.x? I have spent close to 1.2 yrs with xF 1.x.x series ... What xF 2.x would have that xF 1.5.x doesn't has already!