Hello Emre :)

Why 2? Curious about the motivation, here.

For make hardfork you need 17 witnesses from 21 in a round. When round is splited between 10 top and 11 support witnesses, it's imposible to crush network with hardfork not supported by community.

We calculated in chat that 2 votes is enought to make chain in safe from major share attack (51%).
Example: community can avoid any harfork voting with 5 top community witnesses. 10% shares votes per each community top witness. That way major need to split power to many accounts, but he cant get more, that other community shareholders. 51% / 17 = 3%. 3% more lesser that 10%.

Well, i'm agreed, that thoose calculations not good enought, but it simple to calc and explain.
By the way - VIZ chains don't need hardforks by it's mission. Only security HF (if some major bugs will be founded).