Here are some important distinctions to be aware of when discussing Young's Universalism:
1. It is important to distinguish between General Universalism (all roads lead to God) and Christian Universalism (Christ will save all people). The former is not a Christian teaching. The latter is a view that has been held by many Christians throughout church history. It is a possible interpretation of Scripture. Just because Young takes this minority view doesn't make him a heretic. He still believes in Judgment Day and still believes in hell. He still believes that all people are saved by Christ. I'm not exactly sure what the 'heresy' would be.
2. It is important to distinguish between Dogmatic universalism (all will be saved) and Hopeful universalism (all may be saved). Young doesn't come across as a dogmatic person, but he does come across as a dogmatic universalist insofar as he believes the correct interpretation of Scripture (and the correct 'theology') leads to the view that salvation will be actualized in the life of every single individual. Personally, I'm an Free Will Open Theist, so dogmatic Christian universalism doesn't make much sense to me. But, again, I wouldn't consider it a heresy.
3. It is important to make a distinction between Future Universalism (all will be saved in the future) and Present Universalism (all are already saved by Jesus and just need to become aware of this truth). Young is a proponent of the latter. This is a view that may be picking up some momentum, but I consider it deeply flawed. It is one thing to tell Christians that they need to live out their new reality (you are a new creation!). It is another thing to tell people who are not currently following Christ that their reality is that they are already saved! It is enough to tell them that they are already loved and invite them to respond!
I consider this 3rd distinction the most important problem regarding Young's Universalism. Even still, I think it is worth pointing out that, in practice, Young's approach to someone not yet following Jesus would (theoretically) but the same as that of someone who didn't believe in Christian Universalism at all. He'd still tell them about God's love and focus on Jesus as the means to experiencing salvation.