This is not a critical issue but I am interested to see if anyone else has run into it. I am able to start Apple's Maps application in my 10.9.4 guest. However, it never displays the map. In addition, when switching from the 'Standard' view to the 'Hybrid' view or 'Satellite' view, the application quits. I also tested the same action using a 10.10 DP7 guest with the same results. It would appear, even when using the 2D standard view, the lack of a accelerated video driver may directly be preventing Maps to function in a virtual setup.
This topic has been discussed under "Mavericks Maps Issue". For more details, see that thread. In short it's Apple's "fault" and not actually Parallels. If you switch views (2d to hybrid for example) you'll crash the Maps app. Look at the Report or view your Console and you'll see that it died because there was no hardware acceleration found "Unable to find hardware accelerated GL pixel format that meets constraints." Apple apparently doesn't allow fallback to software emulation in the current release of Maps so it won't run properly in a VM.