But I'm not saying he's evil, he could just be wrong or misinformed.
i hold this as very unlikely as he gets his information firsthand "from weaving the threads" or whatever he calls it. that would mean that something so drastic has happened to him that what he sees in the dreams not only no longer makes sense to him, it must also lie to him and brainwash him.
It can depend on your point of view.
Maybe Zoe was doing the right thing in Dreamtime (helping people) and the Vagabon sent her away on purpose.
but this speculation is sterile and he does seem like a strange but good character
Yes, that could be the case, but in that case so many other things don't make any sense at all. Like why is the vagabond welcoming to Zoë in dreamfall and asks her to help him? (remember when brian westhouse comes into dreamtime the vagabond is not very welcoming) and also, why doesn't the white dragon warn Zoë about the vagabond?
This would also not explain why the vagabond is stressing that it's important that she remembers. It would be much better for him to convince her that she has to go back and, in order to keep this place a secret she needs to forget what has happened.
aside from this there's the fact that Zoë was fighting a losing war in dreamtime. she's seen walking around trying to liberate as many as possible, but she's not able to turn the tide. to be able to accomplish change she has to attack the problem at its core. this makes much more sense than any alternative explanation i have found.