The following settings helped me to avoid crashes using DirectX11:
1. Set the DirectX11 off
2. Restart
3. Set DX11 on, but do not restart yet.
4. On the graphics section, set your video refresh rate to 60 Hz
5. Full Screen Resolution
6. Restart
Test the game in the mode you are having the crashes. Mine was WvW and so far it stopped crashing. Hope this one help you enjoy DX11 while playing. Remember: Don't get mad at Anet about the DX11 crashes, since it is in BETA stage, so anything in BETA stage has its bug and we are helping them to find out what they didn't found during dev test. That is the idea of the BETA TESTINGS. Big hugs for you guys, gals and no binary. 😚