Yes, it appears they changed it with the 1.5 update.
We have't dug deep enough into the arduino code to alter the sketchbook location.
To be fair, most people who use Sparki have never touched an Arduino before. We didn't want to burden these people with getting the original installer installed, adding a library, running a separate driver installer, and adding a board file before even getting started. We especially didn't want to burdern a teacher who has to get Sparki started on 20 laptops with doing this 20 different times.
That said, we do offer a seperate Sparki library if you are already running Arduino and just want to add Sparki to it: http://arcbotics.com/downloads
You can run it as an Arduino Leonardo. You're right in that we should be offering a board plugin (which is a relatively new thing), now that they offer the ability to. It'll show up that downloads section when we have it.