If you really want to charge quickly, you aren't going to beat a cable. Just like if you actually want fast network access, you should plug in an ethernet cable. In car wireless charging would be "good enough" if it provided enough power to use your phone as a bluetooth streaming or navigation system without draining the battery. As long as the battery is maintaining a constant charge when using the phone for normal in-car functions, it doesn't really need to be able to top off the battery quickly.
My phone has been off the charger since last night at 10 PM (it's now 10 AM, so 12 hours), and it's still at 100% charge. Because I didn't need to use it for much. Sent a few text messages, read some emails, basic stuff really. It's only when I start using it for stuff like browsing the web, watching youtube videos, or doing active navigation (GPS logging doesn't seem to do much to the battery) that the battery starts to deplete significantly. A lot of that usage comes in the car when I'm using it as a GPS, or listening to bluetooth audio streamed from the web. If I could just stop my phone battery from depleting when I'm actively using it certain scenarios, I could probably go close to a week without actually needing to plug it into a wall.