I am called a traditionalist, and while I can't speak for everyone, I can say that all of them that I know personally accept all canonized Saints (including those after 1965). It is my understanding that this is an infallible decree. I think the only people that are going to argue that they are not Saints are sedevacantists.
I do hear people questioning the prudence of some of the canonizations. That is not to say that the person is not in heaven, but that they are not someone whose ideas should be imitated. Often times when someone is canonized, their ideology and writings/opinions are canonized with them. That is why the process used to be so rigorous, including a "devil's advocate" to dig up the dirt and argue against the canonization.
I will give an example, but a hypothetical one so as to avoid taking this discussion into a "Saint bashing" direction. During the trade center ordeal, a priest chaplain for the fire department was killed. It is said that he was going back into the building to administer last rights (I don't know the truth here, just what I read, but for the sake of argument let's say this is the case). I have now seen where people are pushing for his canonization. Here is the problem- it has been reported by some who were close to him that he was a sodomite (not their words, obviously). I will not argue the state of this man's soul. Perhaps he had confessed this or reached perfect contrition, so now he is in heaven. I have no idea. But, to canonize this man would be to canonize his homosexuality. Were he canonized, I would not question his being in heaven, the declaration would be sufficient. I would question the prudence of declaring him a Saint, though, and would not include him in my list of "Saints to teach the kids about".
That's about how I understand it.