It is a bit of a slippery question. Ch. 4 of the book seems to be going down that route right until the end and then there is a sudden switch, grounded in human freedom, away from the idea that we can know whether all will be saved or not. It is somewhat confusing in light of the rest of the chapter because earlier on he seems sympathetic to the idea that God's love can melt even the hardest heart.
So I guess his view is this:
1. universalism is a valid Christian view, not heresy
2. there are good theological reasons for universalism (he thinks that God desires to save all, sent Christ to die for all, and that there are good reasons to hope that God will achieve his purposes)
3. human freedom means that we cannot know for sure that God will achieve all his purposes.
So I think I'd call him a "hopeful universalist." That mode of universalism (if you consider it to be a kind of universalism) is not uncommon.
I ran out of words in my Baptist Times article and so did not get on to the issue of distinguishing "hopeful" from "confident" universalism. So I simply spoke of RB as a "universalist" which, without the above mentioned distinction, might be a tad misleading.
But this is just my take on the issue but I hope it offers a little more clarity.