The novel had fourteen main characters. Fourteen different story threads. I opened the book by introducing each character at the same moment in time on a particular day. This is called simultaneous storytelling and it's impossible to do in more than an illusionary way. Each character's introduction has to be given a page at a time and by the time I was done with the last one, the opening of my novel was about seventy pages.
The solution is simple: sometimes you have to cut the fat. The best way to do this is to look got characters that seem to be holding you back, characters that don't really contribute to the overall story or don't develop in any significant way. In Harry Turtledove's Colonization series, the character of Rance Auerbach who is on the run from aliens while smuggling narcotics. I've heard that Rance is an example of redemption in Turtledove's story, but I think the main backdrop of the series is the escalating tensions between humans and aliens, something that Rance doesn't really contribute towards. If I were to take Turtledove's Colonization series and re-write it my own way, I'd get rid of Rance entirely.
The advantage of omitting such wasteful characters goes beyond just removing obstacles to the flow of your story. Doing so also frees up valuable page space that can be devoted to the more critical characters. When I screened out my weak characters, reducing the cast from fourteen to ten, I found that I had cut ninety-two pages! Those pages can be used to clarify certain points or to return to characters that have too long of a break between scenes. Fewer characters also means less complications for the reader. They won't have to struggle to remember so many people.
How many viewpoint characters should you have? My rule of thumb is no more than ten. That should give you enough range to cover many different areas of your story while keeping things manageable.