The problem is that it would be mostly useless, because it'd be buried in a menu somewhere where you can't easily change it while driving.
The avoiding tolls thing is absolutely terrible that way. Thankfully, they finally put in a new feature where it shows you alternate routes, with and without tolls, and tells you if they do or don't have tolls. It took years for this to come about even though I had requested it many times, and it's plainly obviously needed. But before this, it was all-or-nothing, and it wasn't easy to change on the fly, and having it on was bad because it would frequently try to route me onto an expensive toll lane even though there was zero time savings, but for other routes a toll road was absolutely necessary.
They should have it weight left turns higher (as in worse) so that routes tend to avoid them. When I drive to work, I can take my normal exit, and only take right turns, or if I miss it, I can take the next exit, but there's a terrible left turn there with a very long light. Google Maps consistently says "1 minute longer" for this route: BS. It might be about the same if you happen to catch the light, otherwise it's 5 minutes longer. I feel like their algorithm really doesn't take this into account well.