A decent approximation of 1.6 with updates to style
Despite players still having the option of playing 1.6 on Steam, an overwhelmingly positive response is on record for the upcoming mod, now in Steam Greenlight.
Difficulties in development present themselves as editing game files can bless you with a VAC ban, but interest seems to be quite large since the project has hit #1 on Greenlight within 5 hours of its submission.
Valve has contacted the developers soon after the project really took off, asking them to hold back the 'Counter-Strike' part of its name. Now the mod will only be known as Classic Offensive, which isn't really a deal breaker.
Whether the mod is just a fad, and if its existence is justified or not in the long term is still an open matter.