Hi guys,
I've been facing the crash issues for a long time.
Symptoms:
1. You can hear the steam startup screen sound, and then it loops and freezes
2. Pressing esc will bring you to the dota 2 load screen.
3. but you will hang there, and then crash and return to windows.

If you face similar issues as above:
Simply replace the d3dcompiler_43.dll in these two directories:
C:\Windows\System32\
C:\Windows\SysWOW64\

You can get dll on the web by google-ing.
Hope I've helped someone because this drove me nuts.