If there's going to be a true successor to 4chan, it's looking like 8chan. Not only will it be a successor of 4chan, but also 2ch and futaba.
2ch refugees are also joining with 8chan, and are going to be opening up a Japanese version of the site and will be organizing advertising to cover hosting expenses for both English and Japanese versions. Why are they doing this? Because what happened to 4chan over the past couple of years also happened on 2ch, where it came to light that the main political party was botting the site to manipulate public opinion, and the moderator staff had become comprised full of government shills.