I'm astonished by that time number. I have a 400 page book, with a 150 page answers to exercises that is emmitted as part of the book compilation and then compiled on its own. I use a simple shell script that compiles each twice (for the cross-referencing). It takes perhaps 10 secs on my five year old middle of the road laptop. Are you remaking complex drawings each time? What is the performance sink, I wonder?
Sorry, it seems like there was a misunderstanding. It takes this on writelatex.com, not my local machine. There it's a normal 7-8 seconds. Just text and about 50 png/jpg images.
My workaround to cut down compilation time is splitting up the document into parts and always only compiling the part I'm working on.
I have tried a similar work around but it turns a bit messy if you are in the paper publication business (which I am). Camera ready copies (final publication) sucks the remaining "work around motivation" out of you.
In case people don't know, there's a built-in command to do this: \includeonly.