It does not seem to be a widespread issue with nMP and D3.
Anyway, without time machine there are not many things to be done. If you have downloaded Mavericks from MAS and you kept it somewhere, you can re-install it. That is:
1. Create even now a time machine backup
2. Re-install from Mavericks media a version prior to 10.9.3
3. Restore your account and applications (but not OS) from time machine using migration assistant
But that's too much of a hassle and it doesn't worth it IMO. Better search for the issue in blizzard forums.