Four major povs isn't that many. Fantasy novels typically have that many, sometimes more. I might question the two minor "one off" ones. I know in my first draft or so I have a couple like that, but I was able to cut them on revision. Of course, every story is different, but I can't remember reading a novel recently that had "one off" povs. This could just reflect my reading habits and tastes, however.
The issue isn't necessarily the number of pov characters, but the frequency of changes. Like I said, when I read a novel with multiple pov characters, I don't count the number of changes (I assume you are only changing at chapter or scene breaks, however, and for a logical reason). I don't even worry about whether there's a balance or pattern in the pov switches. I simply care that the story is moving forward and engaging me and that I'm interested enough in each characters arc to be happy to see their part of the story unfolding.
I have read stories where one of the povs is less interesting to me than others, either because of the way it's written or because I don't see the way the arc fits into the whole. Then there's that, "Oh, ugh, not this guy again," thing that may or may not be a deal breaker, depending on how interesting the other characters are to me to make up for it.
I also read a novel recently where the author presented the different povs as long chunks of chapters without changing too often, and it made me a bit antsy. I think I would have liked it better if she'd switched more frequently, in fact. I kept wondering what was going on with the other characters and how the different story lines fit together, and it sort of irritated me reading chapter after chapter without checking back with the other group of characters I'd invested in during the first group of chapters.
So maybe it has something to do with establishing reader expectations too?