Wow Vitalik hasn't been active on this forum in over 2 years. I know he is worth hundreds of millions but it would be cool if he came back and added some of his insight to this thread instead of only communicating through twitter.
It would be nice for him to return here but from his perspective he probably is happy that he can relay messages and information and press releases in Twitter instead.
Actually he is much busy after the success of this project and now he is using that forum which is much easy for him to communicate with the community. That is the reason he is super active on Twitter but it is not big issue why he is not in this forum.